Current loan is 6.625% (bought for 90K 10 years ago (less than desirable credit back then).I wondered if I could do a cash-out refinance, get 25K and build a 26x26 or so garage with some type of living space upstairs.

To do that quickly, you need an advantage to acquire desirable assets ... or you need an operational gift to efficiently increase their value.Easier to do both when your assets are physically close to you.

@Derek Gibbs completely understand your desire to not shake the boat too much right in the beginning.

There was another thread about a guy who bought in a less than desirable area of Chicago and he was complaining about all the drug deals in his alley (he was also living there).

Real gold aka "pass income" is what my heart desires. 

Having said that, I firmly believe there are way more efficient means to the end you desire. 

There is very little desirable land left so there is no space for large scale development.

vs" you are discriminating against us and we demand you lay sod"..... drop dead....get aggressive with me right off the bat and my desire to work with you just left the building....which will be followed by you.....

You'll have a somewhat basic house (and without trying to be like a jerk, it wouldn't be in a super desirable area of SD IMO) and small garage apartment for $600k+. 

That is the best place to get a true picture of disputes, current licensing and insurance, longevity and whether or not they keep changing licenses (multiple licences for the same person over the course of a few years can indicate less than desirable business practices).