To spend any time on this bus is to be sealed inside a giant bong on wheels.

The soundtrack is Bob Marley, set to a beat of snapping lighters and coughing. Welcome to the "cannabus," a vehicle with tinted windows, about 30 seats, and one purpose: to facilitate the drinking of beer and the smoking of weed.

Someone hands a young woman a pipe containing a super-potent hybrid called Jah Goo.

"I like it. It's niiiice," she says and then bursts out laughing. "I'm really stoned."

For $100 US, the ‘Buds and Brews Tour’ took customers from other states to breweries and a cannabis dispensary in San Diego. (Kim Brunhuber/CBC)

A dozen or so customers from several different states paid $100 US to go on the "Buds and Brews Tour" of a few San Diego breweries and a unique cannabis dispensary, organized by West Coast Cannabis Tours.

Among the first on the bus are Jill and Alan Mayor from Columbus, Ohio.

"You cannot do this in Ohio," Jill Mayor says, shaking her head after taking a hit from a small glass pipe.

Jill Mayor shops for cannabis as though she were buying fruit at the grocery store. She says you don't do that in Ohio. (Kim Brunhuber/CBC)

Back in Columbus, if you want weed, "you have to go to the other room to make the phone call," Allan Mayor says, smiling knowingly.

Not in San Diego, not anymore. The sale of recreational cannabis became legal at the state level in California on Jan. 1 (it remains illegal under federal law). But more than a month later, only a few cities have issued the needed permits.

San Diego was one of the first off the mark. It has embraced the so-called "green economy," hoping to capitalize on a potentially massive revenue stream from taxes and tourism. On this bus are some of the city's first recreational cannabis tourists.

Zac Smith says legalizing recreational marijuana was a game changer for his massage studio, which uses cannabis oil, because it helps destigmatize it.

Zac Smith lights up with satisfaction. He owns a massage studio called Traveling Hands that uses cannabis oil. For him, legalization is a game changer.

"I think it legitimizes it and it does open people's minds up a little bit maybe if they were worried about getting arrested or getting in trouble for consuming or participating in anything cannabis related," Smith says.

First stop on this adult field trip: Ballast Point Brewing. One might assume the beer and weed industries would be natural competitors. But Troy Havins, who's running the tasting room, sees the decriminalization of cannabis as an opportunity.

Troy Havins of Ballast Point Brewing says beer and bud are complementary from an economic perspective. (Kim Brunhuber/CBC)

The company that owns Ballast Point has invested almost $200 million US in the world's largest publicly traded cannabis company called Canopy Growth from Smiths Falls, Ont.

"I think it's good for everybody," Havins says. "The legalization of it just makes sense."

Next stop: a cannabis dispensary. Before the law changed, you needed a doctor's recommendation to buy marijuana from Mankind Cooperative. Now all you need is ID proving you're over 21.

San Diego dispensaries were among the first in California to sell recreational marijuana.

The door opens and in walks one of the "cannabus" tourists, 23-year-old Jordan Fisher. Growing up in Denison, Texas, she used to buy weed regularly, but "obviously not from a store," she says, smiling. "Can I say that?"

For many young first-time visitors like Fisher, this is the millennial equivalent of Dec. 5, 1933, the end of Prohibition.

"This is so cool," she says, as she peruses the menu of cannabis flowers. The dispensary boasts almost 50 types, with names like Afghanimal, Face on Fire, and Chem Jong Ill.

Mankind Cooperative in San Diego is a unique dispensary because it’s self-serve. (Kim Brunhuber/CBC)

"You don't have anything like this from back home, and it's just nice that you can get it so easily," Fisher says, "and not feel like you're doing anything bad because this is wrong. You know it's not wrong."

That is most certainly not the view of U.S. Attorney General Jeff Sessions. In January, he rescinded an Obama-era policy to enforce federal marijuana laws lightly in states that had legalized it. The move could unleash federal prosecutors to target businesses for cannabis possession and distribution, even in states in which it's legal.

Todd Green, founder of West Coast Cannabis Tours, says the industry — even the "weed on wheels" tour he's leading today — is already riddled with legal grey areas. The Trump administration, he says, is now making it even more confusing.

"One week they'll say something, the next week the hype is gone," Green says. "Are they actually cracking down? That hasn't happened yet. So is it going to happen? I don't know."

West Coast Cannabis Tours founder Todd Green says the move is just creating more confusion and uncertainty (Kim Brunhuber/CBC)

Here in San Diego, the fear of FBI raids is distant but real. For many, the biggest concern is much less dramatic. Since marijuana is illegal under U.S. federal law, most banks won't serve cannabis entrepreneurs. That makes dispensaries like this one attractive targets for criminals, says Cathy Bliss with Mankind Cooperative.

"The problem is you have a whole lot of cash," Bliss says. "If we were to have a normal banking system there would be a whole lot less attraction for bad guys to go you know . . ."

Try and rob you?

"Ah, yeah."

Cathy Bliss says the biggest problem created by Sessions’ approach is it will scare off banks from working with cannabis entrepreneurs (Kim Brunhuber/CBC)

Rachel Moberley lights a pipe and then laughs.

"I think I burned my nose!"

She might seem like an unlikely traveller on the "cannabus." Growing up Republican in Virginia, she used to share the attorney general's views on smoking pot.

"I thought that they were losers. Stoners," Moberley says.

Then she moved to Colorado, where she says even her bosses smoked weed with their employees. Despite regularly consuming marijuana, she voted for Trump, not knowing that a couple of months later, his attorney general would turn on the nascent cannabis industry.

"I'm obviously upset about that because I don't think he should be trying to stop the biggest gold rush happening in America," Moberley says.

San Diego cannabis advocates hope the windfall of tax dollars will convince more jurisdictions to ‘go green,’ which may in turn pressure the federal government to be more cannabis-tolerant (Kim Brunhuber/CBC)

California Democrats have introduced a bill in the House of Representatives calling for cannabis to be legalized across the country. It's a long shot, so Bliss says their best argument is the sound of California cash registers collecting the various — and hefty — municipal, county and state taxes, which often amount to almost 35 per cent.

But entrepreneurs like Smith suspects it won't be enough to convince the Trump administration.

"I think him rescinding that memo was more about squashing the industry initially right after they saw the explosive growth that was about to happen with legalization in California and more states," Smith says.

"Now then to come along and say 'oh well we're going to crack down on that;' it's not really reasonable," he says. "You can't really put the toothpaste back in the tube. It's a little late for that."

Victoria Sorrell, 23, samples her purchases at the end of the 'cannabus' tour. (Kim Brunhuber/CBC)

It's time for the "cannabus" riders to head back while sampling their purchases.

​"I hope this bus is going to stop by my house," Moberley says, and everyone laughs.

"Afterpartyyyyyy" someone else yells.

Though they're keenly aware that Trump is trying to end this ride, you get the feeling no one wants this bus to stop.