I instead decided to tear out the old carpet and refinish the hard wood floors and plan on moving upstairs once its done and rent out the lower because its in slightly better shape than the upper.

What can I expect to spend on a replacement of new hardwood for a Main Floor of this house about 800 sq ft?

We had to install new hard wood floors (most homes have them in this market), and when we started prep work we realized we would need to replace the entire sub floor on the 1st level! 

. ($25k)New domestic plumbing throughout ($4k)Wiring upgrades including new meters and service entrance to accommodate new W/D hook-ups in all units ($15k)Installed 2nd driveway, 20' x 37' ($3500)24 new windows ($7200)Gutted and replaced kitchens and baths in 3 out of the 4 units.Refinished all hardwood floors, painted all units, fixed repaired trim, and all interior and exterior cosmetics.4 new sets of appliancesBEFORE                                                                                                               AFTER

The plumping in the house is new and it has the original hardwood floors, that appear to be in good condition and i would only have them re-finished.

Since moving in, we have done the following work:-Sand/refinish original hardwood floors-Interior paint-Completely renovated and upgraded the kitchen-Completely renovated and upgraded the master bathroom-Significant landscaping updates-Converted stairwell to a walk-in pantryWe have done a lot of other smaller, mostly cosmetic projects but those are the major ones.

The hardwood floors and trimwork are in great shape.

Home has a new roof, refinished hardwood floors, updated plumbing, new water heater, new hvac, and more.

I just sold a 1850 house that had new 200 amp service, new gas furnace, new gas hot water heater, new kitchen gutted to the studs, 2.5 baths, newly refinished hardwood floors and other updates.From the outside it looked the same as it did before the rehab.We've had other houses, one of which Civil War Soldiers marched by, and old is not necessarily bad. 

None of the individual tasks are difficult, but you still find holes in your walls, need to refinish the hardwood floors, broken doors, etc after two years.