If you've got a good, controlled way to pick the engine from the bay (chainfall or engine hoist on concrete floor), and the truck isn't completely rusted apart it really isn't too hard of a chore. Assuming basic mechanical capabilities of course.
Do some research on what exactly you need to disconnect/take off before you start tearing it apart (there are a couple threads on here about that).
I did what you want to do, took a running 95 from a single cab truck and dropped it into the suburban. Not as bad as I thought it would be, and I've never pulled an engine or put one in before. (My Dad helped though, so factor that in).
I spent a lot of time reading about what had to be done, so I had a good understanding of what I was getting into.
Tips/tricks?
Consider doing some work to the engine you want to drop in. I ended up pulling the engine back out after 1,000 miles to do head gaskets - definitely would have been easier to do when I had it out the 1st time. I wanted to do them when I had it out, but was too impatient to get it in and running
Pull passenger inner fender definitely. If you can get the downpipe off easily might be worth pulling that as well to give you a bit more room. Not necessary, but might help.
If you use a load leveler (recommended) hook it as low as you can on the engine - otherwise it hits on the firewall and causes problems.
If you don't care for the insulation on the firewall, rip it off. It might be falling apart anyway...and it gives you a lot more room to work with the stuff in the back.
I'm sure there are guys that'll sum up a lot more info that I could, but this'll get you started at least
That said: I have no idea if you can fix the bolt issue you are having, but if you've got a running truck and the bolts can be fixed I'd go that route.