Not a bad price at all considering everything is in good shape. The thing we like about many older campers is they are aluminum skinned, from what we've seen so far it appears that holds up better to branches and brushes when taken down narrow forest roads and 2-tracks. Dents are normal for the "corrugated" aluminum siding, comes with the territory, lol
If you're serious about getting that thing show up with cash for the full amount the seller wants but only show them say 2500 at first and then work your way up as needed. If it's a private seller they may just bite at 2.5k, especially if you start throwing around the cost of Torklift tie-downs and such. Generally people who do outdoorsy stuff like to see their equipment go to other people who like outdoorsy stuff, if you give them the vibe that you will be enjoying their camper or whatever else as much as they were enjoying it there's a good chance they'll cut you a break on the price just to see it go to a good home.