Planning a road trip from Louisiana to Destin, Florida.. Help?

Im 16 && me && my friend Shawn are planning a road trip for 5 people for 21 days from West Monroe, Louisiana to Destin, FLorida.. We're sophomores in high school && we plan on this being our SENIOR TRIP.. We're not sure where to start but we have some ideas of stuff we'd like to do.. We plan on taking my car(seats up to 7 people) && Shawns truck(up to 3) so it'll be roomy either way.. Money at this point isn't a big issue because we don't know what all we want to/are going to do.. The reason we're making it 21 days long is because "I want time to just sit around && be lazy teenagers" (Shawn) lol I know it's like 2 years away but I really want to get all of this planning out of the way.. I need WEBSITES that will help me out a little && any PERSONAL experience or stories or whatever that'll help.. Thanks=) If I think of anything else, I'll add more details..