The Southwind brand from Fleetwood is certainly above "entry level" but not upscale, though there are a wide range of options that can make it quite well equipped. It's reputation has been generally good.
You won't find a 1986 listed in www.nadaguides.com because they go back only about 10 years, but you should find a similar Southwind model from around 1995. Once over 10 years old, condition is everything in an RV, so figure somewhat less than the book value for the newer model, but not a whole lot if the condition is excellent. Figure a LOT less if the condition is not near -perfect.
Don't be afraid to make a very low offer either. There are many, many older Rvs around and many of them were used only for occasional weekends and vacations. Low mileage is common, and well-preserved interiors are also not all that unusual. Look for one that has good maintenance records with it, because routine maintenance (oil changes, transmission service, radiator flushes, etc) is key to keeping a vehicle in shape, especially one that is not used regularly.
Assume you will have to buy ALL NEW TIRES and figure this into your price offer. This is very important, no matter how good the tread looks. Tires have a useful life of only 5-7 years, even if they are never driven at all and stored ina cool dark place. Ifn fact, the less a tire is used the quicker it deteriorates. My recommendation is that you buy all new tires before taking the very first trip in this rig [if you buy it]. Sitting at the roadside with flat tires will really ruin your day, especially when it is your second or third flat in a 100 miles!