Best size TT for exploring the National Parks?

DougE wrote:
Get a small 10x10 tent (or a screened enclosure for your awning) that the kids can stand upright in and a couple of light weight cots. Then you can really cut down on the crowding when the weather is decent.

What I was thinking, too. We've done the tent + RV thing and it worked out well. The only hindrance is if you get into a NP with all the bear warnings posted. All those signs and attention to bear avoidance is a pretty strong motivator for sleeping inside a box and not a tent.