Madison, Wisconsin (CNN) The opening days of Beto O'Rourke's presidential campaign were squarely focused on proving that he is the most electable candidate to take on President Donald Trump -- in part because he will show up.

But his refusal to answer questions about his campaign's structure or fundraising, his apologies for his own remarks and voters' critiques that he is light on substance have raised questions about whether O'Rourke's be-everywhere, meet-everyone approach is delivering what Democratic voters really want.

The former Texas congressman pledged Sunday in Wisconsin to "go everywhere" and take "no one for granted" during his bid for the 2020 Democratic presidential nomination.

"When we don't show up, we get what we deserve, and that is to lose," he told reporters.

O'Rourke's three-day, 13-county swing through mostly rural eastern Iowa included eight counties that Democrats had carried in the 2012 presidential election but lost in 2016. His next four stops -- Wisconsin on Sunday, followed this week by Michigan, Ohio and Pennsylvania -- put O'Rourke in the states many Democrats believe are most crucial to winning the presidency in 2020.

His ability to maintain a grueling travel schedule is aided by his loss in the Texas Senate race last year: O'Rourke can stay on the campaign trail while other candidates who are currently in office have to return to Washington or their home states.

O'Rourke is an electrifying campaigner, and his events have all been packed, with overflow crowds spilling into the streets to see what made him a viral sensation in Texas. O'Rourke jumps onto coffee shop counters, chairs and whatever else he can find to ensure he is heard. But the cramped quarters are partially because that's how O'Rourke's campaign designed them: He's holding events in coffee shops, bars and houses, rather than rallies at venues that can accommodate large crowds.

What's not yet clear is how his campaign is being received nationally.

He told reporters at his first campaign event in Keokuk, Iowa, he plans to "run the largest grassroots campaign this country has ever seen." But so far O'Rourke's campaign has not offered evidence that his entry has begun to create such a groundswell of support.

Google searches for O'Rourke -- and particularly just "Beto" -- soared in his first days on the campaign trail. But no new polls have been released since he entered the race.

One important gauge of interest and enthusiasm for his campaign is fundraising -- which was expected to be O'Rourke's strength after he shattered Senate campaign fundraising records with his $80 million haul last year in Texas. But O'Rourke has so far refused to reveal how much he has raised.

"I can't right now," he said Friday in Washington, Iowa.

A reporter responded that O'Rourke could share his fundraising totals if he wanted to.

"You're right," he responded. "I choose not to."

O'Rourke said Saturday night he'd have no problem with his campaign staff unionizing, like Vermont Sen. Bernie Sanders' staff did , and that he hopes to pay the highest wages and benefits of any 2020 hopeful -- signs that he can afford it. But it's not yet clear whether he has made any big-name hires to orchestrate his campaign from its El Paso, Texas, headquarters.

O'Rourke told reporters in Milwaukee on Sunday that he is "in talks" with someone to be his campaign manager and has offered that person the job. He did not reveal who that person is, but a source told CNN that O'Rourke is in discussions with Democratic veteran strategist Jen O'Malley Dillon

So who is running his campaign right now?

"I'm working with an extraordinary team right now, some of whom helped me in the amazing Senate race that we ran in Texas, some of whom are new to this campaign," O'Rourke said on Sunday.

O'Rourke is settling into a stump speech focused on a call to set partisanship aside to solve challenges like climate change. He told reporters Saturday that he is "trying to find the commonality in the midst of great division."

O'Rourke is also leaning heavily on his life in El Paso on the US-Mexico border as what separates him from other candidates. His passionate answer about the Trump administration detaining children energized a crowd Saturday night in Dubuque, Iowa.

"Imagine your level of desperation and vulnerability," @BetoORourke said at a Dubuque house party tonight. "Imagine at that moment, your child, for whom you literally risked your life, is taken from your arms."



O'Rourke is leaning into life in El Paso as what separates him: pic.twitter.com/PBguqtXHVK — Eric Bradner (@ericbradner) March 17, 2019

He is also delving into more specifics -- including taking an anti-interventionist approach to Syria and Venezuela, criticizing spending on wars over the last two decades and praising diplomatic efforts like former President Barack Obama's Iran nuclear deal. He has also endorsed phasing in a $15-an-hour minimum wage and legalizing marijuana.

And he has won praise from crowds for refusing to criticize other Democratic candidates -- even saying that former Vice President Joe Biden, who will likely compete with O'Rourke for moderate Democratic votes, should enter the presidential race.

Still, O'Rourke has also at times left audiences wanting more specifics from him on the policy front.

"Elizabeth Warren is the gold standard of policy, putting policies out there," a woman told him in Independence, Iowa, on Saturday. "Right now you're doing a good job of identifying what the issues are, but I don't think that really any of us have heard any particular policies that you'd like to get behind."

She then pressed O'Rourke for "particular policies that you are indeed behind" on health care -- leading to an exchange in which O'Rourke explained his unwillingness to embrace popular progressive priorities like single-payer health insurance.

O'Rourke said that he backs a bill introduced by Illinois Rep. Jan Schakowsky and Connecticut Rep. Rosa DeLauro called "Medicare for America." It would allow people to keep their private insurance, but funnel those without private insurance or on other government programs like Medicaid and in Obamacare's individual marketplace into Medicare. It would also allow those with private insurance the option of buying into Medicare.

He said a Sanders-style single-payer "Medicare for All" program would be "wonderful" and that he'd backed it during his Senate campaign, but that "if we become too ideological or too prescribed in the solution, we may allow the perfect to become the enemy of the good."

Earlier in Washington, Iowa, Ryan Turner had pressed O'Rourke on his previous comments that he would tear down the wall separating El Paso from Ciudad Juárez, Mexico.

"I don't feel like he really answered it, honestly," Turner said afterward. "I understand there is a lot of pressure and you're getting a ton of questions, but you know you're asking to be the leader of the free world, and so I think you should be on either side, called to the carpet and be able to back up what you say."

Also dimming O'Rourke's launch were the apologies he made, including one after saying his wife was raising their children , "sometimes with my help," which had infuriated female Democratic activists and operatives who pointed out that a woman could never get away with such a comment while running for office.

In Cedar Rapids on Friday night for a recording of the podcast Political Party Live, O'Rourke said that "not only will I not say that again, but I'll be more thoughtful going forward in the way that I talk about our marriage, and also the way in which I acknowledge the truth of the criticism that I have enjoyed white privilege."

When CNN asked O'Rourke on Saturday what led him to apologize, he said he had called his wife, Amy.

"She said, 'Look, I know what you're trying to say, which is here I am in El Paso, I'm working, I'm also taking on the lion's share of the responsibility of raising our children and you were trying to acknowledge that in your comments but it came off sounding a little flip. And you know, this is a serious thing, and I think you should treat it seriously,'" O'Rourke said. "So I thought that was great advice. And advice that I'm going to follow."

At the same podcast recording O'Rourke also apologized for his writings as a teenage hacktivist that were reported by Reuters -- including one murder fantasy from the perspective of a serial killer.

O'Rourke has also taken heat in the past for his frequent use of profanity. On Sunday in Wisconsin, he told reporters when asked about his profanity, "I don't intend to use the F-word going forward."