When she moved in, it was a small Mini Cooper--I gave her permission to use the outlet on the building (electric I pay for).

The sump pump was put in & then I had the pump outlet extend away from the home & the other gutter, on that side of the home, I ran some black flex pipe from there all the way to the front of the home.

I'm trying to picture your construction and maybe its going into the walls too (depending on the framing), or a chase space . . . if so, look at the outlets/switches as well and see if you can seal them. 

Who can I hire to hold the keys when current tenant moves out, let contractors in for any repairs, and show the property to prospective buyers?

Check with the local codes, but we changed all of the outlets and switches with pigtailed ones, and this satisfied both the city and the insurance company.  

Every switch, outlet, and light fixture upstairs has been replaced.

@Michael Baum I didn’t think of those outlets!

I rarely pay TI but I'm always willing to give out free rent if they need time to build out.  Let

-replace kitchen light with XYZ model from home depot, replace outlets with grounded and new plates-Paint walls eggshell Color XYZ from home depot 2 coats, base trim semigloss white- You can select paint quality as well if you care.I pretty much do this for every part of the house.

A quick and easy way to update this would be to install GFCI outlets at $15 each instead of re-wiring the building.