I used to hobby all the time in South Florida and had some of my best GFEs there. There are plenty of outcall agencies, probably the most in the US. It's the closest thing we have to a Canadian city.
Cost: Yes, the rates are substantially higher than in Canada. No, you will not have to pay extra for being an out-of-towner. But at these rates, you WILL have to plan ahead (pre-book) and there's no room for impulse hobbying.
Illegality: Yes, there was a recent bust of a Dutch man who was running multiple agencies in the phone book. But, he was sleeping with the girls and one of them ratted him out to the cops. And the cops didn't use clients to bust him; they tailed the SPs as they drove from the client's place to the agency's office. Otherwise, I've found that LE pretty much ignores the agencies, based on the number of Florida agency websites I've seen.
A busy prosecutor in the US is going to clear his desk just to nail you with a penny-ante misdemeanor? It's all outcall down there, so the worst that will probably happen is they compel you to testify against the agency ... IF the agency gets busted in the first place and IF they want to use testimony from reluctant civilian witnesses instead of undercover officers. Possible, but unlikely. Besides, that area is inundated with tourists and beachgoers, so a hot chick in your hotel lobby is going to seem very, very normal.
I highly recommend sophisticata.com (especially Gwen, what a body on that chick!) and for lower cost, prettywomanescorts.com has given me good experiences.
