If the house hasn't had a complete renovation at any point then it may very well be a "gut job". By this, I mean, you go in and remove ALL plaster from the walls inside, i.e.: "gut" it. I have always found this to be the most reasonable way to start, especially if you are looking at really old wiring in the walls, cracked plaster and need new plumbing, etc. If you try to replace all the wiring (which it sounds like you need to do) then it is much easier to do with all the plaster gone. This will also allow you to insulate the house, put in vapor barrier, and more easily find and fix any rot in the frame, etc. Good luck!