With an old house like that don't assume anything will be quick and easy. Be prepared to replace things as you go. I recently had to replace a water valve going to a toilet and ended up replacing the old copper tubing coming out of the wall with braided steel lines, it just made it easier. Always over estimate the budget on projects, the little things from the hardware store will nickel and dime you to death. Depending on the state of your appliances(water heater, hvac, ac, etc) you might want to consider getting a home warranty. Keep at least $1000 for oh poo money, more is better. Replace all lighting with led as bulbs burn out, it seems expensive but it's worth it.