I saw this one yesterday and it looks okay. Remember, the price you pay for one of these is only the price of admission.
Almost all of them from that era will require replacing expensive suspension/steering and air system components, updating plumbing, possibly replacing appliances, possible rewiring and electrical component replacement, all window gaskets will need replacing, etc. Bear in mind the tag axle opens you up to more expenses like additional tires, etc.
If you bid on it, make sure you have the right to refuse it if you get there and things are not as represented. You will be protected through eBay's buyer protection program, but do your homework and ask lots of questions before you bid. You can ask on the forums if there is a volunteer inspector in that area who would be willing to check it out in person for you--I believe there is a thread on that around here somewhere.
The "rear plastic piece" they talk about being broken is probably the fiberglass banana wrap, which costs a couple hundred dollars to buy and $$ to replace, unless you can do it yourself. The scar in the windshield cannot be buffed out (if you can feel it with your thumbnail, it's too deep) and it will have to be replaced unless you can live with it. I think the windshields are $600+ for each side, plus the cost to replace them. The dash air is broken (common in older RV's) and will cost $$ to fix. Depending on where you live/travel, you may be able to do without it. Plus, you will want to eventually fix the burned-off clearcoat and replace it--this RV won't polish up like the trailers do, so you will probably want to either re-clearcoat or paint it.
I would guess a reasonable amount for this vehicle would be between $10k and $17k, but that is just my personal opinion. Sorry I can't narrow it down more than that. It is very hard to put a value on these things, not knowing exactly what it needs and all. Some people put them out there with ridiculous price tags, and some of those actually sell. Be prepared to put at least half of the purchase price back into it over the first few years.
I hope this helps! Good luck!