Call a broker in the area or get access to commercial real estate web sites to get an idea for cap rates in the area. 

Several RE companies have good web sites that have loads of  more specific details.

You can build a brand new dream home the land for $150-250k or a magazine worthy Bali bungalow type casita without the land for $1-125/SF. 

Please don't think I'm trying to be negative or troll-y, but if any developer has an algorithm for this, I would wager that developer would be reluctant to publish such proprietary information on the web so they can have more competition.The Knoxville market, and probably most/all of its sub-markets, have cooled substantially due to affordability and lots of other factors.

I'm seeing high electric bills in our STR properties and was wondering if anyone had tried using a web thermostat to reduce power usage when the unit was vacant. 

Search the bigger pockets web site where Scott Smith wrote an article about it last year.

I tried searching the web and only seem to get sponsored ads for firms.

If you do, I suggest keeping it simple and adding a few columns to that spreadsheet to note who replied, who's mail bounced, who is a cold lead, who is a hot lead.To access this spreadsheet on-the-go, you can store it in Google docs and thus update it from your phone or wherever.Of course, if you want a fee-based solution, there are quite a few other (web-based) options.

To get rid of some of those questions from guests you could automate the sending of an FAQ document or welcome magazine with things to do in the area, etc. 

Those the CRFI in Meritt Island have a web site?