I was replacing hardwood floors, helping with tiling, hanging blinds, playing around with light switches etc.

Everything is in good shape, but it’s incredibly 80’s. 4 br 3 bath 2500 sq ft worth with all of these things needed to be addressed: popcorn ceilings removed, new carpet in half, refinish hardwood in the rest, new interior doors, new closet doors, interior paint in the whole thing.

It was the best learning experience, but extremely tiring.I had never installed hardwood flooring, and I put in 1200 sqft alone. 

Just purchased a house that needs new tile, carpet removal, hardwood refinishing, and basement finishing.

Does it have laminate flooring rather than hardwood, a granite-tiled counter rather than solid slab, a fiberglass tub rather than tiled.... etc.Here in Denver, a 500-600K property is a touch above average, but back home in Rochester NY that would be WAY above the average, and would thus limit your selling pool. 

I believe you can rent a nail gun from your local hardware store if you want to do hardwood.

The higher your price range the more picky your buyers will be on "dated" finishes, eg if somehow blonde wood becomes all the rage, higher end buyers will want it but mid-range buyers would likely be thrilled just to get any color hardwoods over laminate.  

The one thing that I think is an issue is it's carpeted throughout, whereas many of the comps I've seen have some sort of hardwood floor, so I figured it would be good to make that change out of carpet. 

I always prefer hardwood.

Also think capex, its cheaper to update a unit that has laminate or quartz counters and LVP flooring versus a unit that marble counter tops and custom hardwoods, so you need to budget more.