A few that come to mind:Since you say the second building is an added bonus, try to find more long term, higher paying tenants (but that should be a no-brainer).

I would like to convert it into a 4/2 by adding that extra wall of Sheetrock in between and another door.

I can certainly make some suggestions on a Georgia-tested lease, but I've gotta say this first...If you're raising the rent anyway, I would strongly urge you to consider adding in enough margin to have the property professionally managed.Property management is where most buy-and-hold investors lose their shirts!

I find less info in the ads are best.

Install new tile and decorative backsplash in both bathrooms (2ndfloor and basement) install new toilets (2) and two new 24-inch vanities with faucets.

@Mike G. in the state of Texas mobile homes are taxed as real property and will be added to your real property tax account.

Adding on to @Thomas S. comment about attitude. 

The many added bonuses of course include that you'll avoid all kinds of tenant-related problems in the room and be able to address all sorts of suspicions, so your notice should read, "under 24-hour surveillance for your protection."

Sometimes this can be done over the phone to isolate the precise location of the leak.Also I just saw an ad for sensors that wrap around pipes.

Driveway for main house accesses front door but  would be better served by adding a driveway.