I can offer insights from the perspective of someone who hires real estate analysts

Different areas offer varying qualities, but most hold investment potential.

This region is well-suited for MHPs and offers unrestricted land.

I understand you tried that and it was rejected but I think you just need to keep putting offers out there. 

And if they did, I'll offer them 1% and be done with it.

I was looking into a virtual number such as from RingCentral so that I wouldn't have to use my personal cell in any guest communications, but I also noted that many of the PMS such as OwnerRez and Lodgify offer SMS messaging.

Both have their own unique advantages and can offer great potential for real estate investing.

You could consider offering to have the shower inspected by a licensed professional to provide a written report confirming its safety and functionality to address your tenant's concerns.If your tenant continues to refuse to pay rent, you may have grounds to evict them for non-payment of rent.

I was recently offered mentorship through a veteran's program for commercial real estate.

If you're going to buy OOS, would highly recommend getting an experienced local investor (someone unbiased, not on the agent's team or anyone  trying to sell you something) to do a very thorough video tour of the property and at least the street before making an offer.