You will struggle for room if you want to sleep in the back of a surf. Not much of a gap between the roof and the floor once you get a layer of mattress under ya
Buy this and get a tent - sleeping inside a truck isn't that comfortable
Fark tenting! They only time you should have to tent is when your tramping

It can limit your days a bit unless you like putting them up in the dark and its pretty miserable putting a tent up in the rain.
I had a LWB high top Safari with a bed setup in the back that was awesome. It was comfy as and was and more than enough room for me and the missus in width and length (although I wouldn't want to be much taller, I'm approx 185cm). Was real handy if we went to a mates and ended up having a few. Didn't have to worry about a taxi, just jumped in the back!
It also went well offroad. Pretty heavy things, but anything you are going to load up with camping gear is going to be. Safari's are pretty easy to mod as well as far as getting bigger rubber under them goes and theres heaps of off the shelf mods. Not always cheap but built tough.
I've got a SWB Safari now and I'm back to tents. They suck.
"Anyone who lives within their means suffers from a lack of imagination." - Oscar Wilde
Work in progress - www.pearls.kiwi