First of all, welcome to IRV2!
I had a 99 Fleetwood Southwind before we bought the 31W, same chassis. It was a good running and driving motorhome. Ours didn't have slides though, so it was rather shortlived. The Adventurer is a much nicer unit.
Winnebago builds a little nicer coach as well, IMO. That's why we went that way, new in 2005.
Here is the factory brochure for that year and model in case you haven't found it, has all the specs too: http://www.winnebagoind.com/products...nturer-bro.pdf
The Adventurer is arguably the most popular model of motorhome ever built. I doubt you can visit pretty much any RV park across the country and not see at least one!
My primary concern for that particular model would be the carrying capacity of the chassis and driving performance. As a comparo, I had the same chassis under a 29', and my 31W has at least a hundred HP more with the updated ECU. I would want to give it a good test drive and get it weighed on a truck scale, front and rear axle, with full tanks, to see how close you are to GVW if not over. My 31W has the same GVW rating and it's 6' shorter. But I am well under gross when loaded, which is CCC or cargo carrying capacity, we have about 3K lbs. Some of the older coaches were really on the border. In newer years they went to a more heavy duty chassis.
Other than that you are faced with a LOT of systems that need to be checked out and verified working - AC on roof and dash, genny operation, fridge in all modes, furnace, slide operation, leveling jacks if it has them, water heater both modes, window operation, water pump, and probly a few things I've forgotten. Inspect every cabinet and cubby looking for water damage from leaks, get up on the roof and check it, slide and shade awnings.
At that age, unless it has been stored indoors or has had the exterior finish updated, will likely need some work. Decals, gel coat, any painted areas, etc.
And finally the chassis - even with low miles you want to have the trans checked out, leaks, engine maint, tire date codes, etc.
Any one of these things can be expensive to replace or repair, so you want to know if there are any deficiencies in deciding whether to offer less or pass on it. It's a rather large undertaking to really check one out. Generally takes me about 2 hours without even looking at the chassis.
Then I would ask you how you'll use it - weekending and short trips, or driving across the country? If this will be mostly parked it will likely be fine. If you're planning to drive it a lot I would encourage you to get something a few years newer and a little shorter on the gas chassis. At that length you are getting into DP territory for decent driving comfort, performance, and carrying capacity. And finally, are you planning to tow anything with it, a car or trailer?
The chassis builders improved dramatically in the following few years. I would encourage you to seek out a workhorse chassis in that vintage with the 8.1 V8. They had a lot more power, the Allison auto transmission, and the wheel track was over a foot wider for better handling and ride. If I'm not mistaken those came out within a year or two of that model. The Ford chassis were updated substantially as well, so worth noting and checking out the progression.
Let us know how it goes and what you find. And good luck!
EDIT: Here's a pretty good thread discussing the pros and cons of the ford and workhorse chassis and motors. Should be quite informative for you: