If you're going in your car, get a full length, full width, full thickness one. Or if you have the car space for it, just go to a mattress store and get a foam folding futon, and save yourself the nuisance of inflating things and fixing punctures, as well as saving some cash.

Even for backpacking, I prefer the full length versions of these mattresses to the 3/4 length ones where your feet hang over the end. I had the Ultralight one for a while and it was ok, but it got lost somehow, so I got the standard (thicker) one, which is somewhat more comfortable, though heavier and bulkier. I've had it for 5+ years now, and I store it rolled up in its stuff sack, which is considered incorrect but I do it anyway because it's more convenient. Perhaps because of that, it no longer self-inflates and I have to inflate it by breath, but that works ok.