Yes I'm good to go on the passport and credit card situation.
I didn't realize temperatures dropped so low. Thats not a huge deal to me, I want to take the trip to get away from school, work and other things that come with daily city life. But you are correct, sleeping in a car when it is -3°C is not entirely fun but I'm sure it is doable with a comfortable mummy bag in the back seat.
I did some calculations using your fuel cost calculator and stopping in such places like NJ, Louisville, Memphis, and Dallas, with a return trip I'm looking at $261 in gas. If i added heading to Phoenix and then Salt Lake City and re-calculated the return trip I'm looking at about $400 in gas.
Using those guidelines is the trip out to Salt Lake City (as the final destination before heading home) feasible in a two week period? or should i call it quits after Dallas?