Keel bolts inspection & maintenance
The keel bolts are as they are going to be. There's really very little you can do about their condition anyway. Your worst nightmare in this case is crevice-crack corrosion, which will eat at the stainless about right where it disappears into the lead (worst possible scenario). And my boat is probably more likely to have that than yours is, because of how it was treated by the PO.
Replacing a bad keel bolt can be done. You drill a new bolt hole down into the lead, etch thoroughly, and screw in a new length of threaded rod with epoxy. This wouldn't be as bad a job as you'd think. A much more labor-intensive way would be to slice out a groove in the side of the keel, lay in the bolt in the J-shape you want, and patch up the gouge with new lead and sheathe in 'glass-- also not really that bad. Lead can be cut with a circular saw and be mended with more lead and a hammer.
When I reset Diana's keel I was terrified of breaking one off. I used a 9-inch breaker bar with 1/2" drive on an impact socket and prayed a lot as I loosened them. Reinstalling the nuts after setting the boat back down on the keel (and two tubes of 5200), I tightened them only little more than hand-tight till the 5200 set up. Then every time I visited the boat over the next three weeks I took about another half-turn on them all with a regular 3/8"-drive ratchet. They have since bottomed out against the cured 5200-- so it's done. My cousin Dave picked up the boat and moved it across the yard before I could warn him about the keel and the worst that happened was that one of my cabin-sole joists parted from the hull (due to hull flex because the keel was on there so well). The new oversized washers are currently set on G-10 backing plates to better spread the load, the touch of delamination was filled with epoxy, and the hull will flex less now when the boat is lifted into the air. Now I have to rebed the parted sole joist to the hull (it probably parted because I had the sole panels loose. Had they been fastened permanently, there would have been nowhere for the joist to pop off to. That's by design).
What I am saying is that bad keel bolts is less of a worry than you may fear. The best way to avoid crevice-crack corrosion is to use good 316 stainless (which the vintage of our boats assures us we have), and to keep ALL water out from contact with it wherever there is no air. This means a good bedding of 5200, even under the backing washers, and keeping good torque up on the locknuts. I don't mean kill them tight. I mean enough that a drop of water won't pass the gap between the shank of the bolt and the inside of the washer. I was careful to not get 5200 on the threads of the bolt-- to do so would make it impossible for the bolts to move up and down through the fiberglass hull, meaning I could never draw the keel more tightly to the 5200 it's set in. When the bedding cured I took off the washers and nuts and added the backing plates, again kept 5200 off the threads, and applied just a little under the washers to keep out the water when I torqued it back down with the 3/8" ratchet.
This will be a maintenance item for as long as you own the boat-- but it shouldn't be a nightmare. Just do your best and let your tools talk to you, as my brother Adam the woodworker says. If you are sensitive to what they and the boat are telling you, you will neither overtighten nor break or sink the boat.