Yep, we own a rent house that has a separate garage apartment in Huntsville, Texas. We have been very lucky with our tenants and have learned a lot about older homes from these homes.
The Garage Apartment is a super cute one bedroom home that has kept the 1950 charm. The home has original hardwood floors, a phone niche and is the best use of space I have ever seen. My daughter in law says it is like a tree house.
When we purchased the house and garage apartment the property was tagged as uninhabitable. The gas meter had been removed, the house had structural problems, and it was just nasty. Now it is a sweet little house with refinished hardwood floors, a bonus room, and exposed ship-lap.