Washington (CNN) President-elect Donald Trump's foray into health policy was perhaps best described by a senior Republican congressional aide with a long history of working through the complexities of the issue as "not helpful."

Trump's decision to weigh in -- telling The Washington Post over the weekend that not only was he nearly done with his own Affordable Care Act replacement plan, but that it would provide "insurance for everybody" -- at once riled Capitol Hill Republicans already in a sensitive position on the issue and underscored the fraught and unknown nature of a nascent relationship with Capitol Hill.

In a series of interviews with GOP lawmakers and staff over the course of the first two weeks of the new Congress, it's clear there is a genuine enthusiasm about the possibilities a Trump presidency presents. Years of fighting losing battles with the veto pen awaiting all of their priorities in the White House are now, in a few days, gone.

But any excitement is almost immediately hedged with some level of trepidation -- there simply aren't many people, if anyone, in the senior GOP ranks who appear to have much insight into what Trump is actually thinking.

Repeatedly in the first few weeks, Republicans have found themselves derailed for a day, if not longer, by a Trump interview or tweet that appears to split with the agreed upon intentions or path of the conference on a given day.

Lawmakers are prone to roll their eyes when asked questions about Trump's tweets, pledge not to talk about them at all, as Sen. John McCain has done multiple times, or ignore Trump's latest surprise policy prescription entirely, as Sen. John Barrasso did Tuesday when asked about Trump's latest health care comments.

"Oh yeah?" said Barrasso, one of the Senate GOP's leading health care policy minds, when CNN asked his thoughts about Trump's statement. He proceeded to walk into a Senate hearing room and close the door.

House Speaker Paul Ryan has a direct line to incoming chief of staff and fellow Wisconsin Republican Reince Priebus, one he uses often, and has said repeatedly that he speaks to Trump by phone a few times per week. Even as Trump has appeared to diverge from Ryan and the House on his proposals, Ryan has steadily maintained there is no major daylight on the big issues.

"We are in complete sync," Ryan told reporters after it appeared Trump was asking lawmakers to move on their Affordable Care Act replacement plan at a quicker pace than planned. "And we agree, we want to make sure that we move these things concurrently, at the same time, repeal and replace."

But Ryan and House GOP leaders have a road map for their repeal and replace process: they did much of it in 2016. While that effort was rejected, whether it was through reconciliation -- the budget mechanism that will allow Republicans to repeal large swaths of the law -- or through piecemeal bills that address the remaining chunks of the law, there is a step-by-step legislative process on which they've already delivered results. All of which were either vetoed or died in the Senate.

The contents of Trump's Affordable Care Act replacement plan were -- and are -- a mystery, according to multiple GOP congressional sources. It's an element, needless to say, that to the extent it exists, wasn't expected to be part of their process, they said.

Ditto in the Senate, where senior GOP leaders are urging caution -- and patience.

"It's the art of the doable," said Senaet Finance Committee Chairman Orrin Hatch. "These things take time."

Sen. Lamar Alexander, the chairman of the Senate Health panel, told CNN he was interested in seeing what Trump and his team put together. When Alexander, who is one of a handful of central players in any replacement effort, was asked if he'd had any conversations with Trump or his team about their plan, he replied simply: "I have not."

Even as Trump rattles off his policy goals in media interviews and via Twitter, he's largely left it to his legislative team to craft and execute those priorities on Capitol Hill, according to a transition official.

That team consists of Vice President-elect Mike Pence and Priebus -- both of whom spent Tuesday in meetings on Capitol Hill -- as well as the incoming deputy chief of staff for legislative affairs, Rick Dearborn. They've been working alongside Senate Majority Leader Mitch McConnell.

A transition official stressed that some of these policies are still in their initial stages and added that when Trump unexpectedly weighs in, he's not necessarily offering up a hard and fast policy proclamation. There's still room for negotiation -- a point made with tax reform in mind specifically.

Trump stunned Capitol Hill Republicans when he appeared to reject the idea of a border adjustment tax in an interview with The Wall Street Journal . Just a week prior, Trump's top lieutenants, from Priebus, to son-in-law Jared Kushner, to chief strategist and senior counselor Steve Bannon, were on Capitol Hill for a nearly two-hour meeting over dinner largely focused on tax reform in Ryan's office. One person with direct knowledge of that meeting said Trump's apparent opposition to the idea never came up.

But in an admission that seems to encapsulate the frustration GOP officials will face repeatedly in the months ahead, a person familiar with the Trump team's internal discussions on the border adjustment tax even said that it's not the actual tax Trump objects to. But rather, Trump doesn't like framing his plan as a border adjustment tax.

"Some of it's the marketing," this person said.

After Trump weighed in on the border adjustment tax his spokesman, Sean Spicer, downplayed the distance between the President-elect's policy visions and the legislation Republicans have been crafting on the hill.

"I think we're having some serious -- some discussions back-and-forth with key members of Congress, the House and Senate leadership. When we have something to announce, we will," Spicer said Tuesday. "There's always a back and forth between the executive and Congress as to how to get this right."

The question, at least on the congressional side of the relationship, remains whether those back-and-forths will lead to firm agreement -- or just something waiting to be undercut later by Trump himself.

Hatch, the Utah Republican who has been in the Senate for more than 40 years, chuckled when he was asked if he thought Trump was starting to understand the complexities of Capitol Hill.

"I think he's getting there," he said.