Clickman, Welcome to Texas! You're a brave one to consider the plunge into what I would view as the border of
remote Texas. Residents of South Texas may not agree but that's why we call it South Texas.
I did some web searching and came up with a few links that look worthy.
Texas Escapes has some brief info on Runge as well as the
Handbook of Texas. Neither gives me a hankering to look further.
Finally,
Texas dot com has some usable info on Runge, including some real estate links. It appears the real estate is in other towns.
My observation is that Runge is at the intersection of two state highways, neither of which goes anywhere and is about twenty miles off a U.S. highway between San Antonio and Corpus Christi.
The weather would be pretty warm (hot) in the summer and not too cool in the winter, with year round humidity. The terrain will be relatively flat and mostly brush.
Again, it's brave of you to want to jump down there, wishing you the best.