I can't give any specific advice on camping but I can on fishing the Sabine.
If you want some of the best White Bass fishing in the State then the Sabine will fit the bill!
If you want a little float trip then you could put in off Hwy 79 out of Carthage and float down to Joaquin/Logansport and it is about 25 miles.
If you want it a little shorter you can out in off FM 2517 out of Carthage toward DeBerry and it will knock off 10-12 miles.
The areas North of Joaquin/Logansport is chock full of Sandies and the like so it is prime fishing waters.

I lived one mile from the Sabine where it crosses Hwy 43 between Tatum and Marshall for several years and spent countless hours with a line in the waters of the Sabine.

BigDozer66