There is nothing illegal about Subto when it is done legally, as you infer.Actually, Due on Sale is a result of banks calling loans due back in the 70's and 80's, simply because interest rates had increased and other spurious events like that.

This is primarily why I plan to get a property in Old Town Alexandria whenever I can (THE HOMES HERE ARE EXPENSIVE) currently I do airbnb arbritage here and it does phenomenal, I read through your report which furthered my confidence in this area, and I'm excited to keep holding onto property here.

Sold with extra lot for value increase Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

Before we started the flip he had filled me with so much confidence in his ability, then once work was underway it was one excuse after the other.

I agree with @Jonathan Greene that the question is vague, so my advice will have to be as well.The short answer: MTRs are real estate, so just like all real estate, any place that can long-term-rent cash flow with increasing jobs/population can be a suitable site to purchase. 

On the other hand, investing in some repairs (if financially feasible) might significantly increase the property's market value.Remember, each property is unique, and what works for one might not work for another.

Quote from @Lionel Quiambao:  ... and maybe throw in the option for the tenant for more speed at an increased rent to cover the additional payment. 

I know I put the work in already to get to this point, and though I've had the confidence or the manifestation knowing all along I could do it without a doubt, it still shocks me at times that I was able to do it by myself with zero guidance and just intuition and a cant fail attitude!

Another rental is in a great area but has struggled recently due to increased competition from newly built apartment complexes.

I’d recommend looking for properties that already have stable tenants or need minor updates to increase rents down the line.