Returns have been fantastic and I do believe it is a strong, up-and-coming market not many are talking about.One thing not many investors talk about with STRS is going the experiential route and leveraging social media to drive tons of bookings. 

Certain organizations such as the AICPA and the State board that issues the CPA license mention what a CPA can / can't do to retain his / her license.Providing a comfort letter is an 'attest service'.Furthermore, CPA firms are encouraged to have insurance, which may mention that the firm can not provide comfort letters.What the mortgage company is looking to do is potentially have another person to go after if the mortgage goes south.It is not worth it to a CPA to get a few hundred dollars but potentially get a lot more in risk exposure.

Some companies offer social media marketing as well. 

Consider contacting a local real estate mentor or joining a real estate investing organization for assistance.Good luck!

Does anyone have recommendations for an STR on-call service (not full property management), which will handle basic guest communication during their stay and handle organizing repairs (i.e. calling a plumber, HVAC, etc. ... not actually doing repairs themselves)?

You can also offer to assist them in small ways, like researching properties or helping with social media.

All the social media accounts and gurus are no longer touting how to strike it rich in real estate.  

I will only live in one of the units 4 out of the 12 months of the year because the other 8 months I will be with the Angels organization, during that period they provide a place for me to live and also food, so during those 8 months I would have more money I could save up and use in my house hack.

@V.G JasonI agreeEven if fed reduces rates it will take months before it has any impactThe job market is far worse than media is making it out to be due to it being an election year.

Pay close attention to the capital stack, how much debt there is, how much preferred equity there is, how much the GP is co-investing, how much they project rents to rise organically every year, what exit cap rate they're assuming, how much cash reserves the property/investment will have, how much does the deal returns change when you add 50-200 bps to the cap rate, what is your breakeven occupancy and exit cap rate, and a bunch more.