Yah, the green and brown thing are rather critical. From the amount of rust it has been wet too much too long. The stuffing box can be repacked, but you probably would want to replace it before the rubber fails, and clean up all the rust to see what shape the shaft is in under it. Also, the cables/tubing that are running alongside it don't appear to be secured properly, I'd worry about chafing failures and if the red cable is a battery cable--a fire.
The wood is sunbleached, there may be structural damage from going unprotected for too long. If you cna find someone who will still inspect a wooden mast--they may tell you to replace the mast and boom, and that may eat your entire repair budget. A conventional aluminum mast is simply stepped, held down by the tension of the stays (and more recently by a pin or bolt into the shoe) and the way those screws are all lifted, would indicate there's been a lot of movement there.
A purring engine is good...but I think a proper survey could give you a bill of specifics that you could use to reality-check your refitting budget. In any case, make up a bill of goods yourself and price 'em up. Rigging and sails, with nothing else, could also eat up your budget.
Could be a bargain--but one major slip, like needing a new mast and boom, could also double the price of your entire project. (Purchase AND refit budget combined.)
The nicest part of being a pessimist, is that it is always a pleasant surprise to be wrong about these things! [g]