Now..I'm not steppin on any toes here... but you should do this right the first time...or pay more in the long run. Your trying to fix an issue that is one of the most important parts of your home. If your looking for a new answer, everyone here... all professionals, have already said. Remove and replace. There is nothing to think about, but you are able to do whatever you like... and suffer the leaks when those big rains and snows you talk about show up.
My advice, get a few roofers out to give you quotes, see who will work with you if you already have the materials, Barter something you have, or can do.... but just don't half *** the roof... your just waiting for it to leak. Then the stains start inside, then the mold, then the damage triples.
Call your local bank, credit union, State office for small loans. You know the drill. Try the trade schools.
Talk to local organizations, Church groups that donate money to help out, anything you can think of... it never hurts to ask. My wife's great grandparents borrowed money from their church to by this farm 100 years ago.... paid them back in 2 years after they did so well with the farm.. Interesting ain't it.
Good luck, and PLEASE let us know what happens. It is a cute home.