For example:1) Class type- B/C class2) ideal property size- 16 or more doors3) Vacancy rate- nothing below x%4) Absorption rate- 5) Cap rate / coc return- etc..I realize that everybody will likely have different goals for investing and will be in different markets so this will drastically change certain answers to the above but if you could also share your actual numbers alongside the checklist this will be very helpful to me. 

At first glance the rents for that area seem a bit high based on the size and location. 

Forget the fact that San Antonio is a big city,  there are pockets of areas and different classes of properties that have their own cap rates, vacancy rates, etc.According to the latest census the average family size in the USA is 3.2.

Size of the property matters. 

Location, size (BR/BA SQFT) and pool would also help in determining nightly rate. 

.): The distance from the property line of the front and side walls, porches, and exterior features of any proposed new construction must be compatible with the distance from the property line of similar elements of existing contributing structures in the context area.The exterior features of new construction must be compatible with the exterior features of existing contributing structures in the context area.The scale and proportions of the new construction, including the relationship of the width, overall height, eave height, foundation height, porch height, roof shape and roof pitch, and other dimensions to each other, must be compatible with the typical scale and proportions of existing contributing structures in the context area unless special circumstances, such as an atypical use, location or lot size, warrant an atypical scale and proportions.The height of the new construction must not be taller than the typical height of existing contributing structures in the context areas unless special circumstances , such as an atypical use, location or lot size warrant an atypical height, except that:a.design guidelines for an individual historic district may provide that a new construction with two stories may be constructed in a context area with only one-story contributing structures as long as the first story of the new construction has proportions compatible with the contributing structures in the context area, and the second story has similar proportions to the first story; andb.

How does that figure in the size, use and cost of this garage?

It’s a very small sample size.

I self manage currently but when I get to the size that i don't want to deal with it anymore thats where I'm going!

There are some undervalued properties in some less known towns, but even in those mid sized cities like Povoa de Varzim and Vila do Conde the prices are way too high.Unless you are considering doing AirBnb, pretty much, exclusively.