However, will probably do some improvements to it, if I decide to rent again within the next 365 days.

Most of the  value here is improvements he has made and has depreciated  over the years.

Here's the link for ReVision Energy's solar hot water. 

Can I buy a property for $100K & put in another $100k from my funds to improve it?

My personal feeling is that it's a lot of risk, and you should focus all of your energy on your core business, not real estate.

Note the other instances of ROI such as Dividend Yield, Interest Yield, Net Income Yield, Net Operating Income Yield (aka the infamous "cap rate"), these are all different types of ROI.ROI is a generic concept of how efficient an investment can generate return as such it is a concept that is applicable in investments other than real estate (i.e. stocks, bonds, etc). 

Also, would a bank appraise the property if they did none of the improvements?  

The “seller” will buy back these two tracks with the proceeds of MUD bonds he sold to reimburse himself for advancing $8 million for utilities improvements.

In fact, most of the "housing distortion" you see in these markets I think can be identified from the regulations that were trying to solve a real problem but just got in the way and either made building new apartments more difficult, or maintenance and improvement of neighborhoods more difficult. 

The finish on the floor is much harder than the finish on fine furniture, but they may be able to quickly and cost efficiently blend the scratches for you.Also on the cheap you might be able to get a scratch blend crayon from the floor manufacturer for your color, although don't expect the results of a professional blender.Just a thought.Good Luck!