I understand your quandary. Over the 28 years I have messed with dulcimers, for me, I have found that second to the sound of the dulcimer, I need to enjoy the looks. I do like nice looking and well finished wood. From what you are saying, it sounds like you may have a hard time enjoying the looks of this dulcimer. (perhaps I read you wrong?)
There a number of people on this site who can give you some good advice on how to clean this dulcimer up yourself--I am not one of them. Perhaps you could get the build up off the tuning machines, get them oiled so they work smoothly and get the wood cleaned up to look nicer. Then you can play it and save up for one that is nicer with a shorter vsl. I have personally purchased more than 5 dulcimers, several sight unseen, which were bought by the original owner as an impulse buy, played very little if at all, then put away and stored. One of them still had the noter stick and the pick sealed in its little envelope that had not been opened. I say this to let you know that used or second hand dulcimers are not something to avoid out of hand if they have been stored in a home with controlled temp and humidity--not in a rental storage unit, not in a damp basement or in a hot attic.
Just my 2 cents. Best wishes with this project whichever way you decide to go.