I use this product to sleep in my car! Although if you can accompany the greater width, I'd go with the larger size!

I am 6'4 and find the smallest size available a little too small. Tossing and turning is difficult.

HOWEVER, this mattress never runs low on air, and fills up quickly, self inflation! If you are shorter stature and don't weigh much, the smallest size is perfect for 1, 2, 3 nights even longer.

Very happy with this product!

Superb comfort, restful.
JUMBO size (mine is largest: 77 x 36 x 3) for my big, rectangular bag (consumes the better half of my 2-person tent)
Inflates quickly and fully. Repeated packing and inflating will also help.
very lightweight considering its size.
Material seems very durable, hand washable. My large sleeping bag also remains on the bag in spite of nigh-time shifting, so for me it's superior to any air mattress (personal preference, opinion).
Pillow is a minimalist wedge, a bump, yet just enough (personal taste).
Best for base camping, it's packed space requirements will likely make this your bulkiest item on your pack.

Tough to pack, so you will earn your comfort. I plan on adding helpful directions and pix.
Lightspeed descriptions totally accurate.

So comfortable. I slept really well on this. It's pretty firm but plushy. Only downside is, while it's very easy to inflate (just need to open the air valves), it's hard for me to deflate. The air inflating is very powerful, and for every bit of air I manage to squeeze out, a good bit will come back in once I shift my body weight. Finally I got someone else to help me, using both of our knees to push out the air as we slowly roll up the pad.
Also, might not be so convenient if you're planning to take this to backpacking. It's a little bulky, and quite wide.

Highly recommend. Very comfortable. Only part that is super annoying is trying to roll them up. They do not fit well in the compression bag that they come with. I still can't get them back in, because they keep reinflating. I wish they would do what the tent companies do and add a zipper with additional space for later after you use the mat. A compression bag you can unzip and that extends the space after you use it. If they create this I would love to just get the newer compression bag. Again I love this mat and so does my family. We bought 3. They are so comfy and quick to inflate.

This pad the most comfortable solution to sleeping in the great outdoors I've ever found. I've tried air mattresses (too "bouncy", bottom out when I sleep on my side), huge rolls of memory foam (comfortable, but took up WAY too much room in my little Subaru on camping trips), and even a collapsible cot! (took up almost no room in my car, but was very restrictive and I couldn't move or turn over... a little like what I imagine sleeping in a coffin would be like!)

This mat is PERFECT! It is about 3 inches thick once it fully self-inflates (no huffing and puffing!) and, because it has a core of foam it doesn't go completely flat even if you forget to close the air valve. (I assume this would also mean that in a pinch if it got a hole in it, you would not be miserable until you could get it repaired .) I am 5'8" and can lay on this with room to spare. I also weigh 190 lbs, and I am able to kneel on this without "bottoming out" and feeling the hard ground on my knees.

Putting this thing "away" was the most challenging part of the experience for me. You basically have to open the valve and start slowly rolling it up. I found that by kneeling on the roll that I was creating, it squeezed out more air. Once you get it all rolled up, close the valve and then unroll it again. Then start re-rolling it as tightly as you can (with the valve closed!). Once I squeezed the remaining air into the last foot or so, I opened the valve a tiny bit and finished rolling the last bit before quickly closing the valve again.

Packed away in it's handy carrying bag, it's about the same size as your average folding camp chair.