The main component is that it has to be propotional. 

So, my main question is whether or not we are overshooting or undershooting with our 15% budget or should we allocate more since it was build in the 1950s. 

I plan on purchasing mf in the downtowns of the cities surrounding Houston, mainly those with a more “Americana” type of feel( white picket fences, 4th of July block parties, neighbors worship together, founding families are still around and they let you know it, high walkability score, families are out on the street with neighbors, doors are unlocked.....)It is tough to comp certain property because they might be the only type (or one of the only two) AND some of these towns do not allow any more MF to go up, so the MF owners set the market.

The main reason I care is I don't want to have to spend $1000 or more every year on the tax prep when all I probably need to do is file on the Schedule E (especially with just one or two properties). 

Main home should pull in $800/mo due to other rentals/apartment pricing in area.

You brought up a good point on the fixed income - mainly through social security.

Main home should pull in $800/mo due to other rentals/apartment pricing in area.

One of the main questions when starting is if you need a real estate license which you don't.

What makes the college area so attractive? 

You may have to get creative...find a duplex in a good area and Airbnb the units or find an SFR with a legal accessory dwelling unit and live in the smaller unit while renting out the main etc.