I'm going to be driving from Illinois to Colorado for a long weekend on the Fourth. The drive, in total, is estimated to take 19 hours, so I'm going to need to stop somewhere along the way and get some sleep. So, two questions: 1. I have a twin-sized air mattress. Think it'd fit (in my 2010 Prius III) if I flattened out the seats? I've slept in the back before (directly on the floor/seats) and loved the skylight/rear windshield, but it certainly wasn't the softest bed I've ever tried. 2. I really don't want to attract police attention for pulling over on the side of the highway (or a local road, for that matter) and getting some rest. Suggestions for [legal/advisable] places to stop? I've seen people mention Walmart parking lots, but I'm not sure how they would feel about having some 23-year-old setting up a bedroom on their property.