We have a 1988 25ft A/S and have found it to be maneuverable and a good size for the two of us and the cat. Our longest continuous use of it has been about 10 weeks so can't speak for full timing. Our trailer has the original axles and have religously had the bearings greased every 10,000 miles or 2 years (which ever comes first). Also the power jack has been serviced every two years and is the original. You may want to run the fridge to be sure it is okay, possibly the PO can start it up 12 hours in advance of your picking it up and you would have a better idea of it's soundness. Our fridge gave out soon after purchase. ) You may want to pull the wheels and check the brakes or possibly the PO can give you a towing demonstration to check the brakes as a more immediate measure.
We know one couple who tows their 23ft A/S with a Road Trek. It meets the weight criteria, but can't remember if it was a 190 or what. They use the Road trek to branch out from the campsite for short trips while the trailer remains in the campground for longer periods. Also use it for other guests to stay in when camping or a getaway from snoring spouse!
I love the trailer and have been happy with the size of it. We tow it with a GMC duramax which works out well for pulling grades. Our previous tow vehicle was a 99 Suburban 1500
5.7 ltr with the 3.73 rear end. It was a four speed and was very week pulling the 25er up any grade at all.
Hope this helps, Pat