I have a '94 Ute that looks almost identical, (
http://s659.photobucket.com/albums/uu312/LittleBuddy73/Camper/) other than being a little longer, and having the sink and stove reversed. Mine is 8.5', and has a potti-closet in the back on the pass side, but I'm turning it into a pantry.
My truck is an '06 2500 GMC. On the road, it's completely fine. I did some pretty decent offroading over the weekend (Lots of climbing with with rocks, switchbacks, and water diversions, a little mud...) and will say that you can sure tell it's there! 9000 lbs of truck and camper is not terribly "wheelable" in my book, but the truck and camper did just fine anyway. I think my camper is on the order of 1500lbs ready to go. (water, gas, food, stuff...) If you're really wanting to "offroad" and not just travel backroads, fire roads, etc, you are either going to have to go very slowly, or find a light weight FWC or similar unit.
It is a wood frame camper, but I would like to think it's one of the better built units out there. Mine has some dry-rot under the edges where the jacks mount up, so the plywood is soft and the jacks have sunk into the sides. (I think it sat on the jacks A LOT before I got it, which you're not really supposed to do with this style of jack... ) I would look under the bed, as well as in the bins up front to check for rot. Also of course the sides and underside, but from the pictures, your jack mounts are solid, so I bet the rest is too.
I paid $1800 for mine a few months ago, so the price for yours seems good to me. Great if the side plywood isn't rotten, and the soft sides aren't water stained or torn at all!!
If you do intend to go offroad some, I would consider bolting it down, at least in the front. My camper is sitting on a rubber bed mat to bring it up to tailgate height, and turnbuckled in the corners, and I was able to slide it around some in the bed this weekend. And it likes to move forward and push against the front even just traveling on dirt roads. I'll probably toss a 2x4 up front next time I have it out, or add some snubbers to the front edge like the new ones have, so it pushes against the bottom of the front of the box rather than the top rail.
Good luck!
Chris