Wilabong,
Folks here in Maine get by OK with 2WD on trucks, so you should be OK in Penn.
It all depends on your driving habits and tires. Like Ryan suggested above, get good new tires, but I would recommend to change them out when the original tread depth is approaching half way gone. (front or rear) Some people can wear out tires after 20K miles.
It's good you're thinking about it now, and asking for opinions. With that approach, you'll probably NOT be one of the folks in the ditch this winter.
I like the idea of using tube sand - it doesn't take up much room and won't be shifting around as you make corners.
Take care,
Tom