In retrospect a concession may have been a good call.

In retrospect I placed equity in properties up higher as a goal than cash flow and consequently I have not maximized the cash flow on either of my properties by not utilizing financing.

Although I vested in this deal as myself the property is held in an entity that is not mine (its an LP)  so in retrospect I guess can't do a 1031 anyway. 

It worked out ok for us.I did some landscaping which I liked when I lived there, but it was too high maintenance when we moved and I managed it as a landlord.I did some "home improvements" because we were excited about our first house, which in retrospect did not help might have hurt the rentability.One year after we moved to a house, my wife got a job offer out of the area and we moved.

In retrospect I would have looked into other lenders and options, possibly commercial financing.

In retrospect I would have done a 30 year / 5 year adjustable loan; however, it turned out to be a great situation.

In retrospect, probably better to save money the last 12 years and bought 1-2 properties.

Or it common practice for them to attempt approach the owner, with a buyer, retrospective?

In retrospect, that was probably putting a bit too much trust in the other side.

That book helped me get started on my path along with another book called The Complete Guide to Buying and Selling Apartment buildings (which ironically I feel was not really a complete guide in retrospect!).