I was able to teach me kids how to do certain projects that we don't do often at our house (electrical, plumbing, etc).

The only things I call to have done is the plumber when it involves a sewer snake (roto-rooter), or if the plumber has to certify a gas system is free of leaks (I don't have a plumbers license), or if something electrical has to be done by a licensed electrician (I don't have a plumbers license). 

Keep in mind that multi's usually have common area electric and sometimes even water, those expenses are the landlord's to cover.

One of the things I would take into consideration would be maintenance costs so a 1940s property makes me question the age of the plumbing and electrical, two of the most expensive problems to have.

You need to learn to evaluate markets and various housing systems (electrical, plumbing, etc) to make good investments (IMHO) in this space. 

In my county, if the unit isn't connected to the house, then separate water and electric needs to be run. 

I train contractors in the HVAC, Plumbing and Electrical industries.  

It sounds like you haven't spent much time working in an electrical panel, so I'm not sure I'd recommend this as a first project.

Obviously the 'mentor' doesn't like this guy and just wants him to stop bugging him lol

Replaced all windows, doors, flooring, painted, enclosed a porch, redid kitchen and bathroom as well as a lot of electrical upgrades (running new wire, adding circuits) only hired help was roof repair, plumbing, and some of the electrical.