We had no problems with the flights. I think we went Dublin - Atlanta - Atlanta - San Fran - Sand Fran - JFK - Shannon with Delta. Most of the Airlines let you do this online. Second time we just went Dub - ORL and reverse but we did some driving within Florida. As you say two weeks in PCB or indeed Orlando alone would be hellish. Check out Kayak.com as well for good deals.
The first year we flew to Atlanta and drove (8 hours?) to PCB and the second year flew to Orlando. Both were fine but did involve significant driving. The first year we spent te week after the race in San Fran and the second in Orlando. Two very different holidays! There are some great flight deals on internal flights in the US but traveling with the bike is a bit of a pain.