Help. Building/mid term hold

[Bill Bob]

Alright. By chance, of the 4 properties i own, two are 1+ acre. One could easily hold 2 homes, one might hold 2.
I live in the Tacoma area, and my properties are in desirable areas near a large mil base. I can hardly find a thing about the expected cost to value, and that makes me gun shy. I don't have hundreds of thousands to through around, and want to continue to climb the ladder, so my adversity to risk is moderate.
My questions are:
1) Should I leave well enough alone (still making cash flow).
2) Should I build homes on them, and hold for a few years.
3) is there enough money at stake to justify a small time investor doing such a thing?

4) Lastly, I just found a smoking deal on 5 acres with a tear down. I At first glance want to build a primary residence of which I would inhabit for what I assume would be up to 3 yrs (about the time the military will move me again).

Alright folks.... Your thoughts.
Thanks in advance.

WB