RE agent, I currently reside in IL and interested in potentially investing in the Columbus or Dayton areas.

There's been talk of how these will intersect and it's already happening in some spaces and I'm not talking about Metaverse Real Estate (Although I think some of that will make some people VERY wealthy).I'm talking about real physical real estate providing access to crypto investing and returns, and here's the crazy part...It has the potential to offer all the great things real estate does like depreciation, hedge against inflation and cash flow, all while exposing you to the high reward of Bitcoin's upside and decentralized nature. 

I plan to retire from FSU as a mechanical engineer/machinist in about 6 years and want to research a potential  entrepreneurship in short term vacation rental properties.

Like Michael mentioned, your best bet for this would to be to have either a CMA done or have an appraisal done.

HOA now will be allowing max 3 rentals per year, which they say avoids the potential "grandfathering" issue.  

Your best bet is to allow them to break the lease and keep the security as the early termination fee.

You probably cannot legally build a taller fence so a trellis or similar is your best bet. 

Has anyone ever worked with investor funding group ?

I’m assuming it’s just like everything else, won’t learn it (or potentially get any sort of leads) until you do get it.

Real estate can provide a more tangible asset and potential for rental income, but it requires more management and can be less liquid.