Off the top of my head, depending on the location, you could: build a solar panel array, create a covered parking area that rents at a premium, donate the land for a tax break if possible, create a pocket park and generate a new energy for the neighborhood, etc.

As for Electrical, aluminum wiring is a red flag not seeing it can't be used but it has greater chances of malfunctioning and causing a fire vs copper(aluminum was used more in the Vietnam era but this is just precaution), make sure all electrical work is grounded (you can tell if the receptacle are 2 prong and not 3), Service and Panel size would also need to be adequate if you plan on adding more rooms and circuits(I recommend at least 150 Amps).

Since that time; they've done quite a bit work and replaced (or are still in the process of replacing) most of the big ticket items like termite work, the electric panels,  all appliances, flooring, etc. 

The property, where of all things, I changed out the electric panel and made it a 200 amp service, saw the value rise higher than the property I did nothing with.

The house has been on the market for a while and comes with tenants in both units who are paying a lot less than market value rent.We are planning on doing the kitchen later this month and maybe solar panels to boost the value of the home.What do you guys think ?

We'll get ahold of Centerpoint this week to get the gas meter moved and the electrician will start later in the week demo'ing out wiring and starting to pull new for the new layout as well as we are moving the panel.

Control panel, base station and a few motion detectors. 

Looks good though, a more roof like appearance then standard solar panels.

One repair like a furnace or electric panel will eat up all of that cashflow.

I've also used vinyl siding and corrugated panels for surrounds and it didn't look too bad but it requires marking the studs.