Senior trip help?!?

Ok, so me and my cousin (who are now sopres in high school) are planning a trip in 2010 for our senior trip to Florida. We live in NC and there's going to be about 8 of us combined; 4 guys and 4 girls. We're planning on getting a 15 penger van so we can carry all of our baggage and us, staying in Florida for about 2 weeks, and staying in a hotel in Kissimmee,Florida(I was thinking of the Emby Hotel). We are going to go to the 4 parks in disney world, Wet'n'Wild, Busch Gardens and Sea World. Me and my cousin are going to get jobs this summer and the next so we can save money to go to this trip, but the big problem would be gas because it's almost 4 bucks here already. Also, me and my cousin will be the only 17 year old seniors there;the rest are all 18. I know it's kinda early planning, but we really do need to plan ahead of time. So, if anyone has some tips,advice or good deals feel free to tell me! Also,we're going some time in june 2010