... Howdy ... It's A Good Bet If The Seller Tells You That Some Parts Need Cleaning What They Are Actually Saying Is Needs New Brakes And Possibly A Starter Too ... Give The Bike A Good Look Over And Get All The Bikes Repair/service History You Can ... Happy Trails ... P.S. I BELIEVE THAT THE 81's ARE GL 1100 NOT 1200 ...
I like the 1100 series but these were made only for 3 years and I've heard parts are tough to get. If you're in to a restoration and locating obscure parts is your first interest, the 1100 will be a good bet. If this is about riding, why not look for a 1200, fix the stator and ride for years to come?
To address your question of possible price/value, I bought a '82 GL1100 Interstate a couple years ago. It was a pretty nice, ready to ride bike with about 70,xxx on it, if I recall correctly. No show piece, just a decent bike. I gave $2300.00 for it and thought it was a reasonable price for my area (Southeast Missouri). If the bike has "issues" that would need to be taken into consideration.
I currently am working on a '83 GL1100 Interstate I bought last summer. It was "neglected" for a few years. Lots of work done with only a few parts needed, so far, but then I haven't even tried starting it yet. If all goes well I will have bought it for a song We'll see though.
They actually built the 1100 for 4 years. 80,81,82,83. The brakes have no adjustment so look for caliper or master cyl problems. Look to replace the starter. You can tie up a good bit of money in bikes that need work. If it hasn't been started in some time look for carb problems. If you look around you can find a nice running good shape GL1100 Goldwing ready to ride for less that 2500 dollars. There is a guy in my area that has a nice 81 GL100 Interstate for 2200 dollars and it's ready to ride anywhere.
Sorry to hear about you losing everything. You are not alone. My advice would be to shop around and find a bike ready to ride. They are out there and you will come out cheaper.