Besides the elements that Michael has brought up, a few others that you need to keep in mind while planning this trip include:

How well do your best friend and your girlfriend's best friend get along? Inevitably you and your girlfriend will want some alone time together, leaving two (essentially) strangers to pass some time together. This could get very awkward if you haven't clearly thought through what you're doing.

Check here for some rules of thumb on estimating costs for your trip and here for some tips on keeping costs down, but Michael is right in suggesting that you get everyone on the same page as to what kind of RoadTrip this is before starting out.

"California to Florida" covers a multitude of sins. Anyone would need considerably more precision before being able to recommend "must sees". Just for starters: Will you be travelling I-10 or I-40? What are your interests? What do you mean by 'conservative' - political? religious? fiscal?

Finally, As Michael has correctly asked: What are you planning to do on those 3 out of four days you are not staying in hotels? You've come to one of the best places (in our humble opinion) for planning, but you've only just started.

AZBuck