May I ask, How much experience did you have when you flew in the US?
I originally got my JAA PPL in the USA....then went back for a few flying holidays, then did the IR (pre Visa days
), ME, CPL etc.....We flew to Vegas and other places even just after getting the PPL though- sub 100 hrs or so I think.
If you have never flown there before, read up on the rules and regs (Google FAR AIM), and expect 5 hrs with an instructor - not because you need it legally, but probably because you will feel more comfortable. If you go to the West coast make sure this time includes a mountain checkout, and if the LA area, get a Catalina checkout. Catalina Island - great, hill top airfield - do not get low and slow though!
Regarding rentals...If you say to a flying school you want the plane for 3 weeks, you might be able to negotiate 15 hrs per week. I'd also negotiate a "dry" rate as it makes it easier, rather than having to keep all the fuel receipts to knock off the rental costs when you get back.
I recommend this place, so long as you don't want to fly sh*t
:
www.californiaflightcenter.com
have fun!