Thanks for your reply again Auto E. Jetblue fly the route too for under $100, and US Air aren't much more for the dates we're looking at. There are only two of us but I appreciate your point about the relative cost.

I will try to price up the one-way with the big guys but I did have a go previously and it was coming out very expensive. I think we're favouring the option of two cars and flying in between. Therefore, I'd still be interested in the car types and tire questions.