I have been wanting to get a prius in large part not only the awesome FE, but I like the idea of using it as a "mobile tent". I have seen people that put the seats down and are able to get a fairly decent sleep accommodation add to this the ability to leave the AC on with the engine shut off until the batter gets to a certain level and gets recharged (does the same work for heat as well?).

I am wondering if this is also a possibility in the highlander hybrid. I know its about 1/2 the gas mileage but I like the SUVs still up in the air, anything is better than my 12 mpg i have now . Only planning to use this for sleeping on the rare occasion of camping, and long road trips where its really not worth it to pull over at night.

BTW i am 6'4 I slept in the back of rented Mazda cx9 with my GF one freezing night in Massachusetts and got quite a good nights sleep.

 

YOur biggest issue might be your size. You can do this. A typical gas car (non-hybrid) burns about a quart of gas per hour to idle. I would think the hybrid would reduce this by about a 1/3...but that is speculation. No reason you couldn't.