$8000 for a 2003 with all those options that work is not that high of a price. The wing are easily fixed and replacing the sift spot in the floor is no biggie either but that's if the stringers (floor joists) are still in decent shape.
Although, it's not much of a job once the soft spot in the floor is cutout to lay another stringer next to the one that may have some rot starting with Gorilla Glue on the joint side of the new reinforcement and screw it tight against the existing stringer. Wet or water/moisture is what activates Gorilla Glue to foam up, expand, and cure and it very strong. Then, put a new piece to fit in the cut out hole and screw it down with some bridge blocks under the joint on all 4 sides so it can't tip when walking on it. Fill the recessed heads to flush with a plastic filler to flush so the Vinyl doesn't get depressed dimples in it where the screws are and lay the vinyl back down. Fixed and stronger than new and even looks like new! BTW, be sure to dry out the about 3" deep basement under the hole with fan or some heat for a couple days before closing the floor hole so it doesn't continue to decay/rot. May have to replace some of the insulation material you can see if it's soaked.
I did this to a friends about 5 years ago and it still solid and you can't even see it'd been repaired. He had a hose coupling break from freezing and it rotted part of a stringer and 7" X 11" area near the bathroom door.
A lot of loaded with options TC for $8000 and the 915 is a very nice popular model! It would easily bring more than 8 grand in Michigan or the Midwest as we had looked for one for our grandson for over 2 years before we found a 2002 915 last summer with a lot less options and no generator and he gave $7350 for it to a private owner after a lot of haggling. NADA low was $8140 as optioned.