The house next door, also a duplex with exact same floor plan but in better shape, last sold for 125k.

Maybe the current tenants don't care, but if they are also below market rents and you start bumping their rents, will it be opening the door for more complaints or increased likelihood of them leaving because they are being impacted by the smoker.  

But we do have a few duplexes, four units, and townhomes in the mix that skew the appraisal values and per-door numbers. 

What's behind that door, in the garage, how's the mechanicals look, is their water stains anywhere on the ceiling, etc. 

My c class units, built in the turn of the century, make $500 per door.  

Not a huge deal in my opinion and it may open the doors for more negotiations if i need to find other financing methods.

That gets me in the door for the first year. 

Typical cosmetic (lifestyle) upgrades we do are better/more LED lighting, dimmers, flooring, paint, trim, solid wood door slabs in place of the hollow core etc.

we have 3 properties. but the best benefits to me are the message templates and automatic messaging and door coding, along with being able to handle direct bookings.

I've not done that remotely, but it could be done.I have a handyman that gets used appliances all the time and installs them in my rental houses when needed.It would take some trust or coordination on your part but could save you some substantial money.I'm sure you could find someone on the next door app that was handy and had a truck to go pickup stuff.