Based on my recent experience in purchasing a 2002 Itasca Suncruiser 35U, your biggest concerns will be age-related as opposed to specific model issues. If you're not a DIYer, having things fixed is going to be much more expensive if you're going to pay $100+/hour to a shop. First impressions are important. If your first impression isn't good, walk away. One rig I looked at was newer than the others I'd seen but the PO had lived in it for two years while between houses, and it looked it. Ask about how it's been used. If your first impression is good, then start your objective review:
1. Leaks - Look for signs of leaking, discolored headliner, delamination outside, etc. Inspect the roof carefully. Read up on the Winnebago windshield leak issue and look for the signs (water stains on the dash is one). I would think that a high percentage of rigs that age will show some signs of leaks, so it's going to be a judgement call or at least a bargaining point. Significant sidewall delamination and rusty (not just leaking) windshield frame would be causes for rejection. Skylights, vents and other fittings can be re-sealed and/or replaced.
2. Equipment and Appliances - Your priorities here are the high cost items, generator, HVAC, water heater, refrigerator, Energy Management System (EMS), etc. Here's a link to a current posting on "basement air":
http://www.winnieowners.com/forums/f...ir-350544.html
Note that the basement air has two compressors, only one of which will run on less than 30 amp service. This means it can't be fully tested unless plugged into 30 amps or more. There may be a way to test #2 compressor by tripping the breaker for #1 compressor, but I'm not sure:
http://www.winnieowners.com/forums/f...mp-139654.html
Most other "house" equipment, such as the water pump, etc. is relatively inexpensive to replace if you DIY. I'd plan on replacing the converter (about $200 DIY) since the existing one is harder on batteries than currently available converters with multi-stage charging. You also should consider replacing the batteries unless they're new or a couple of years old (6v golf cart batteries are a good idea).
3. Hydraulics - Make sure all hydraulics (slide outs and jacks are in good working order. Look for signs of leaks, primarily at hose fittings. Hose's can be replaced but it can add up. I had to have three slide out hoses replaced. Again, there are numerous postings on this.
4. "Truck" Issues - This was my biggest concern since I'm a DIYer and felt confident about fixing most "house" issues but not "truck" issues. You're buying a big truck so you need to make sure it's in good condition like you would with any vehicle except this is BIG compared to a car or pickup. I'd suggest having it checked out by a good truck repair shop (Ford or Workhorse depending on the rig). Transmissions, and engines can be expensive if there are major issues. I had the shocks replaced (about $400 + parts) and the starter in addition to a minor A/C fix, tuneup, lube/oil (not cheap). You'll read a lot on the forums about the pros and cons of various shock absorbers, some of which are quite expensive. I'd suggest sticking with OEM unless you have the experience and knowledge to choose something different.
Get a vehicle history report (Carfax or similar). This is especially important given our recent storm/flood history.
5. Based on my experience and what I've read on the various forums, budget about $4,000 over the purchase price for the above. If you get away with $2,000, count yourself lucky. It's typical when buying a boat to negotiate a price contingent on a "sea trial" and survey. I'd suggest the same with an RV. If the road test and professional evaluation identify any issues you can walk away or re-negotiate the price. Make sure whoever does the evaluation is qualified to evaluate both the "house" and the "truck" or have two evaluations.
6. Price- Prices are highly negotiable, especially on older rigs. A comparison of asking prices to NADA values will give you some idea. Dealer prices seem to be especially inflated. Two of the owners of rigs I looked at (one of which I bought) had recently taken them back from dealers who had them on contingency because they weren't selling. In both cases, the owners immediately dropped their Craig's List price by 20% - 25% from what the dealers were asking.
In evaluating various models, make sure the floor plan lends itself to comfortable use with the slides "in".
Good luck.