I
>figure someplace like Oklahoma City is pretty darned central, and somewhat
>bearably warm in Dec/Jan (as opposed to Sioux Falls)

Good idea, but I don't think Oklahoma City would be much fun camping in
January, although I have never been there at any time.  How about South
Texas, like Big Bend, or the Rio Grande area of McAllen or Brownsville?  Or
South Florida, there Is a great State Park near Sebring, Highlands Hamock
(sp?) State Park.  They are definately a little farther, but if you are
going to get away from cold, why not get away...