I might be wrong about some of this, I've never actually read a sign at a disc golf course around here.
My home course Veterans currently has 20yr old signs that are apparently not very helpful, although we have a plan to finance these and a group of guys in charge of this project. the important thing to remember is the first hole is on top of the hill, up the sidewalk from the south parking lot. i think it is all navigatable for the most part but i notice people get lost trying to find hole 8. So after hole 7 continue north up the trail that leads you over a creek with a nifty boy scout built bridge and you will come out on top of 8's teebox.
Zboaz, i dont think they have tee signs, but like it has been pointed out you will almost always have someone to follow or join up with.
Crowley has a good map online i think, there is one at the kiosk, tee signs? i dont think so
Rockwall, John Houck, nuff said
Cedar Hill has signs and i think its fairly easy to navigate, but there are two courses that run next to each other so print a map just in case.
I dont know, i guess take maps for all of them.
Better yet i know there are plenty of unemployed DFW golfers on this site so find a tour guide