Glenn, welcome to the forum!
As far as the economics of doing all this, if you have to pay someone else to do it at standard shop rates, it's probably cheaper to find another Cub that's been already reconditioned, or one that's been gently, but regularly used and well-maintained. From the sound of things, you probably have enough there to fix it up without breaking the bank too badly on parts, if you have the time, tools, skills, and gumption to do the work.
Try to do an honest evaluation of the tractor's condition as if you were going to buy it. Since the tractor's been in the family, you have firsthand knowledge of it's history, but don't let sentiment cloud your judgment too much. A $100 102 I got last year with the intention of using parts to rebuild an old 102 that's been in the family since I was a kid made me reevaluate my strategy. The "parts" tractor was a better restoration candidate than the one I intended to restore.
Here's a few things to look for:
Engine: Don't expect to hook up a new battery, and pour some fresh oil in the crankcase and fresh fuel in the gas tank and expect it to light right off. The engine may well be "stuck" if the spark plug was left out or a valve was open when the tractor was parked. At minimum, you'll probably have to clean and rebuild the carburetor and clean the ignition points. If there was fuel in it when it was parked, you will have to deal with that smelly sticky goo that the fuel will have turned into, it will need to be removed from not only the carburetor, but the fuel tank as well, along with any rust that may be inside the tank. Not terribly expensive if you DIY, but pretty messy.
Clutch/Transmission: If you have memories of the transmission popping out of gear regularly, that could be a show stopper, as new gears are expensive or NLA, or it could be a bent shift fork or weak detent spring, which is fixable. If you remember the transmission as being okay, then worst case for a new driveshaft, spring, disk, and throwout bearing is a couple hundred bucks. You might not need everything, if the spring and driveshaft are good, you might only need a disk, which is less than $50. Look around the flea markets and other places for a decent used clutch assembly.
Steering: The steering boxes all get sloppy as hell eventually, but they can be disassembled, cleaned up, and adjusted. There is a pretty good FAQ on the website on how to do it. The left hand spindle can be a problem part, the hole tends to wallow out. Check the tie rod ends, if they are loose replace them or upgrade them to Heim joints, as I have done with my nearly completed 102 rebuild. Pull the wheels to check the condition of the wheel bearings. They're not terribly expensive, but the little things can add up after a while.
Electrical: Check for cracked insulation, broken and frayed wires and repair any unsafe wires. Rodents in a barn can do a number on electrical systems. Clean your ground connection, hook up a good battery and crank away. Troubleshoot as necessary, check for spark and starter operation.
Tires: TSC prices are about $30 each for the front, $60 to $70 for the back.
Seat: Figure $70 for a decent seat if you can't live with the one that's on there.
Hope this helps
Bruce
