On the other hand if you are in a hot climate being up in the air is a big benefit. Additionally with the quick set up/break down of the RTT you get to easily take it with you when you move. Have something to sleep in if you do not make it back, if plans change, and you have the security of knowing your stuff is safe..
Me and my wife can set camp or pick up camp in about 5 minutes and that includes getting the boys and all there crap set up. We are able to keep a complete set of dishes and every thing we need for camping in the trailer. Go camping has never been easier for me. Grab a few clothes, a couple of bikes, and some food hook up and go. It is fun to watch people set up tents who don't camp all that happen, I have seen couples almost end relationships as they struggle over pitching a tent.
Its all about how you want to camp. For me climbing up on top of the roof to camp would be a PIA, esp. with kids. If you don’t want a tent of the ground I would get a utility trailer and pitch it on that. I have spend allot of time "roughing it" while in the Army and don't do that anymore.
When I take my family camping I like to come and go often to the day, fishing, swimming, hiking, Ranger shows, whatever. Having to pitch a tent all the time would suck. It is nice to come and go from camp through out the day and have your shelter ready for you when you return.
I cannot see any practical reason to pitch a tent on a roof of a vehicle. I can see wanting to be off the ground, but a tent on the roof of a vehicles seems ridiculous to me. If i is only two and you want to keep it simple sleep in the back of the 4Runner.
To me it seems like it is just a way to be different, maybe cool to some, but just don't see any benefit.
I have camped in windy areas where it is all you can do to keep you tent from blowing way, I remember one time chasing down my tent at Joshua tree. A tent on the roof that day probably would have been destroyed.
