jharry3 said:
I would not trust the old wiring especially if its that old fabric insulation stuff. I am thinking an update on that including a new box with real breakers. Besides rotting insulation the rodents have a tendency to gnaw on wire so it probable has some open spots waiting to cause you trouble. If you start using the place you probably will quickly overload the old electrical system.
I would put in Carbon monoxide monitors to verify your heating system is not going to kill you.
Septic system could get expensive; probably needs new drain piping, tank and field updated.
Other than upgrading/inspecting the two things that can kill you, the electrical system and the gas heat, you have a place with a good roof that needs a lot of TLC.
When I was in high school, my mom and dad bought a cottage that was about that vintage - think I remember about 1902. Some lath and plaster, but also some 24"-30" heart redwood-sided walls with newspaper, muslin fabric, plaster, and paint over the wood. The structure was in surprisingly good condition, considering. Foundation was redwood posts sitting on native rocks. All of that had to be replaced.
The thing that it had that was somewhat terrifying was knob and tube wiring (Knob & Tube) . Where the wiring passed though a beam, there was a porcelain tube. Push button light switches. Wire had fabric 'insulation' with no ground. Fuse panel had screw-in glass fuses. Thankfully, none had pennies under them ;=)
We removed all of the old wiring and installed a new breaker panel, wiring, switches, and outlets first thing.
If it has that system - which any part that dates from 1905 and is unrestored would - I would replace before I even thought about staying in the house.
Edit - Regarding plumbing, I lived in a 1930's house that had 1/2" galvanized pipe. Every bit of it had rusted to the point the opening was down to the size of a pencil. Couldn't replace anything since the pipe was so compromised that it would break before a fitting came loose.