Get a Motor Vehicle Use Map (MVUM) at the rangers station. It will show you where the Forest Service parcels are, as well as any open roads into the forest. In the upland pine forest I'm sure there are dozens of places where you can seclude yourself and never get caught. Now if you plan to hang out with the locals at party spots/campgrounds, you will likely be subject to ranger scrutiny. Know the regulations and know your rights.
I traversed the Gulf Coast last December, but did not stay in the forest. Weather that time of year is somewhat variable. On Christmas Eve we had a low of 76 degrees with rampant mosquitoes and unbearable humidity. Then a rainstorm came through and there was a solid week of clouds and drizzle, with temps hanging in the 50s day and night. The Mississippi Gulf Coast may not be paradise, but it is affordable and unpretentious.