A few friends and I plan to take a road trip across the US and we are starting to plan now. The thing is we are having trouble decide where to go and what we need. Any help?

start with what are your interests then find places that match...

If you answer is "2 weeks wildnerness hiking & camping" that will point in a very different direction vs "art museums & theater shows" or "laze on a beach"

You need to provide more info if you want help.
How long will you be traveling? What is your budget? What are your interests?

Please let us know which city (or coast) you want to start at and what season (spring, summer, fall). Instead of a fully road trip, I like taking a train and then renting a car and making a loop and then going onward on a train to the next stop which eliminates some of the "flyover country" like Kansas or Nebraska.

I see 2 downsides to tomfuller's suggestion, depending on the details of the trip, of course. 1. Expense. One car vs several train tickets. 2. The ability to be spontaneous overall which for me is one of the best reasons for driving.