It's a fairly big thing here, most people use 4-wheelers, but me and a couple of friends have gone creek riding with our big trucks, (Well, my Blazer, a 92 2wd half ton Chevy and probably the coolest Jeep Liberty around) It usually ends up with me and the Liberty dragging the C1500 out of the mud and through the water. But we have gone almost 40 miles on one of these trips, around here the creeks are public property, as long as there is flowing water and it is a certain width. The creeks we go on are usually pretty shallow and have big exposed sand bars or mud.
One time it was just me and the Liberty guy, and we started up on his property and followed it for just over 30 miles, all the way to the Mississippi, then we went up a little ways and found another creek and followed it until it just turned into something we needed boats for.