I'm done a lot of drywall replacement and patching, but only one house did we take down to the studs and redo the entire drywall.Mike

I have a few homes that I need to start replacing windows.  

Found out for sure that the roof needs to be replaced.

I just mention those as andidotal stories because I like to tell stories and I have been developing land since the late 70s and I have a lot of them.In CA it can take decades .I just did 7 lot split in North  Charleston SC and that was done in 120 days start to finish.. but it was on existing streets.... so just platting.I have a 23 lot project in Portland going right now... we will put the first stick in the ground 2 years from when I went into contract.. we started the underground in July and will pave next week.to be fair we have had a brutual winter .. and my excavator failed a Sewer pressure test and had to replace 300 ft of main line ( on his dime).. but with those two things we are 3 months longer than we like and with a 1.2 mil loan even at 6% its 20k in extra holding cost.When your doing development any dollars less than 100k are just small bills  LOL.

Also, appliances need to be looked at and replaced from time to time.

For example replace the entire faucet not just washer.  

There is no replacing a certified appraisal, but a cheaper option could be to get a Broker's Opinion through a local real estate agent/Broker.

Cat urine horror stories,, are you prepared to replace dry wall up from the floors at least 2 feet and all the base trim,, carpeting, and probably sub floor...

This will be a total strip down including the cabinets which have already been removed, acoustic ceiling, flooring, wall paneling windows, doors, interior walls, floors, appliances, (water heater will be replaced with a much smaller tankless water heater which will give us an additional 32 cubic feet (4sfx8') of living space.Above the furnace will be replaced with a sub floor heating system which will allow us an additional 32 cubic feet.

I know you have to keep the historical integrity of the house but the backyard is large and the roof must be replace anyways.