How hard is this to fix?

Accidental smack of the cable yesterday popped the input on my ampeg loose. In the second picture, you can see the pieces kind of stuck together again, and it looks like all I really need to do is get a hand inside to hold things in place while I screw the threads back in from the outside, but I have never opened this thing up and I don't know how difficult that is. Wondering if I should just drop it by a shop that does amp repair, although it would be kind of cool too fix it myself and save some cash.