Replying to Road trip / USA Advice?

I am about to embark probably on the most epic journey of my life to date. A 9 day trip from Toronto to LA. Its over 4000km each way and listed as 36 hours of driving time. It is myself along with 4 buddies. We are driving it straight, then going to beach it up and what not for 4 days or 5 then drive back home. Last minute cheap get away reading break trip. I have been on several road trips of about 20 hours or so, I dont know about one that is near double in length.

Post up some advice you have, things to do, anything that can make this trip be good. We are going to probably end up finding a place to tent out like a park or something, and im sure find a cheap motel one night in the middle to get some solid good rest and shower etc. Sounds pretty dirt bagin but what ever im poor.

Thanks guys. Oh, and i herd gas is way cheaper in the states, what do you guys pay per gallon? Constantly distinguishing between USD and CAD, Litres/Gallons is going to get confusing.

Advice?