This is a developing area of case law but they may need more than just a letter from a doctor depending on how far you wish to press the case.

@Tushar ShahConsider the following: Take a logic based approach same as you would if you want to be an doctor or engineer.

This allowed me to get some hands-on experience, build up my credibility (showed that I can find good deals) and my confidence which, in turn, benefitted me when it came to time to raise private money.I know fund all my deals using a mix of hard money, private money and/or seller financing (seller carryback or sub-2).By the way, prior to learning about REI, I was teaching science labs and working on my doctorate degree at UH (which I happily abandoned), so no REI experience at all. :)Good luck!

They are a doctor or have some other back story they think ads credibility.

At one time the property was a doctors office.I looked on Zillow for the homes similar that was sold in the last 6 months and it is around $110,000 to $ 120,000. 

When a doctor wants to relocate his business, I want to be the person he calls for property or demographic research, or I want to be the person a local broker calls when he needs help with forecasting.

Unless you already have multiple assets you want to protect, with a lot of equity or a business/profession (e.g. doctor) you need to separate from your real estate activities, you shouldn't concern yourself with an LLC - it will slow you down and eat your cash flow and other resources. 

@Eddie Salisbury  if the Feds enact another GOZONE for Harvey and for Irma ... you have to buy property in the affected counties however with Katrina it was a wide swath .. it extended all the way up to Jackson MS... which is where I invested.The program was open to any full time real estate professional... what you could not do though is say be a Doctor and then claim Gozone bene's  now there where a lot of shysters putting phony LLC's together .. as you know any great deal like this is going to bring the bad people out.. but upon tax examination they got their deductions disqualified plus penalties..

I'm not sure about your clientele but a lot of our investors are busy and successful professionals such as doctors, CPAs, engineers, project managers, entrepreneurs, etc, they do not have the expertise or the time to look for and qualify investment properties themselves.

We also have a STR, but next year we found a solid tenant (doctor) that wants to rent it long term at a small positive cash flow. 0% credit card debt once the adu is finished, and thanks to Biden student loan for wife will be gone.