You are also in the northeast which is crazy expensive to heat, especially if using electric heat.

Would you need to add/extend plumbing lines / change the electrical panel for the dryer voltage.

To switch from the Electric trucks to petroleum based trucks.

Seems that the tank was "rented" and owned by the propane company and they wanted their tank back.We have also switched many properties from oil heat or electric heat to more economical natural gas. 

I'm just beta testing a few different options to work the bugs out before I open it up more broadly.

My concern is there are window AC units which could result in much higher electric bills in the summer. 

With this, I could essentially charge a flat rate for electric to the units.

Mostly small things, biggest things have been a new electric panel, appliances for one unit, fresh paint for one unit, new garage doors.

Also, having enough equity that people are bugging me for it is truly a nice "first world" problem to have.

Some of the things that have happened during the last 7 years of running STRS, loose deck boards, rotten outdoor steps, broken interior hand rail mounts, loose electrical outlet...Any of those could cause a major accident so they were repaired asap.