What you describe sounds like a good fair deal. Nothing to brag about, but perfectly reasonable. I have bought a dozen Ms, mostly on ebay for between $15-$50 shipped, and about 3 at second-hand stores, not working, for about $5 each.
If you think that spending an hour at the workbench and kitchen sink, taking things apart and tidying everything up sounds like "fun" then you should be satisfied with the project and result.
Triple the time and spend more money, and you can do a bolt mod later.
Model Ms are great fun because they disassemble into a bunch of parts and very well built (except for the rivets).
And lastly, you can't know what mechanical keyboards really can be without using buckling springs for a few hours, at least.