Charlie,
Parts are readily available and inexpensive, it just takes time. If you had to pay shop rates for the repairs I don't think it would be worth it, but that's up to the individual. Between on-line forums and You Tube Videos there is information on most all aspects of restoration, you just need to do a little digging. I will tell you that as a guy that never even changed his own oil to completely tear down, inspect and repair the parts of a hydraulic system and when finished pull the lever back and watch the 3 point lift smooth and stay there with a load on is a pretty neat feeling. They claim that ole Henry made these tractors so that the average farmer could do most of the repair work in the fields, all I can say is that I have a new respect for the average farmer.
I would say if you have a little time and just tackle one thing at a time it would be a good family project. I was turned out to pasture in May and going a little stir crazy. I have been puttering around on it since July and I look forward to each step. (My wife calls it my mistress cause I spend so much time with her.)
Here is a link to a forum that is on my favorites list:
Ford 9N, 2N & 8N Discussion Board
and:
How-To's - Library of Tutorials Written by Our Visitors
I paid $2,000 for the tractor and have spent somewhere in the neighborhood of $500 on parts. It will never be able to do some of things that a new Kubota will do but they are available for a fraction of the cost and I liken it to having a 27-2 as compared to a slicked up AR-15. There's a time and place for both of them.
One last thing - as someone mentioned you can just buy one that someone else has already restored for around $3,000 to $3,500 so your not going to save a ton of money doing it yourself, but then again, "THIS ONE" is your Dads so I'd imagine your mom would give you a pretty good deal on it
AND BEFORE YOU GET STARTED, BUY A CAN OF "GOJO."