I live approx one and a half hours north east of the circuit.
With all respect to Pidge (who I've met a number of times now, both at Sebring and Daytona) Miami Int., isn't the obvious airport for Sebring, as far as I'm concerned. I'd use Orlando International, Tampa, or Orlando Sanford. The latter is a 'charter' destination (Airtours, Britannia, My Travel etc). Assuming you're prepared to slum-it with the white-leggers coming over to see The Mouse, you will probably save a good chunk of cash vs a scheduled service. Of the schedule airlines, I recommend Virgin Atlantic, direct, from Gatwick or Manchester into OIA - or US Airways, into OIA via Philadelphia. Both are good value and good service.
I book a lot of hotel accommodation for my US dealers in O'town, so I can get some quite aggressive room rates at swanky Disney hotels or decent downtown places too.
As stated earlier, I don't have the stomach to live at the circuit for several days beforehand - a bit pointless for me - but given that lodging is so dirt cheap here and the pound is so strong v US$, I wouldn't think it's much of an issue. Don't bring tents/bags - they cost piss-all here - but do bring something waterproof. The circuit is quite exposed and can get windy - if it rains, it comes at you sideways.
Dave H and Fax usually occupy my guest rooms on the Friday before and immediately after the race, but I'd be open-minded to putting a roof over the heads of 2 civilised CAers for a couple of days prior to the race. I also have a very large Dodge pick-up, in addition to my 2 seater, so I could do a little fetching and carrying also if needed.
Smokey, if you'd like me to organise something a little more 'executive' than Daytona beachfront, I'd be happy to - though if the lure of trailer-trash, jail-bait and biker-momma's is just too great, stop by Lollipops - it's the best tit-bar in Volusia County (the strippers outnumber the punters, which is pretty f**k*ng funny).
Additionally, I'll be over at Daytona for Bike Week. We've had two 1800cc Honda Runes delivered here, so me and the owner of one (I'm neither!) of them plan to scoot over and see how they sit, next to the rows and rows of Hardly Movingsons.