There's a very slight chance that the Allentown SC will be up by then. Keep an eye out on the thread:
PA: Whitehall ( Allentown) Superchargers Updates - Page 50
Otherwise, have you checked around to see if any there are any owners nearby with a CHAdeMO adapter you could borrow for the trip? People seem to be friendly like that. I arranged to borrow one no problem from a fellow around here, although I ended up deciding not to make that particular trip in the end. Probably a bit late for that, but....
EVTripPlanner says an 85D will use 252 rated miles to go from Hagerstown to Tannersville in 32 degree weather with 72 degree cabin temp. Doable, but extremely marginal. The direct route is a bit of a charging desert on the Tannersville end, too, so you wouldn't have options to bail out early for a slow charger.
If I were doing this trip, I think I would route through Allentown. EVTripPlanner says that route is slightly more efficient anyway, at 245 rated miles. Allentown has several publicly accessible J1772 chargers that could be used as backups if it looks like you won't make it. I'd do a 100% charge at Hagerstown, pre-heat the cabin thoroughly, then turn the climate control off until it got as cold as I could stand it, relying on the seat heaters as much as possible. Drive as slowly on the interstate as you think is safe. Speed and heat will be the two big range eaters here. Keep an eye on your projected arrival SOC, and in particular whether it's going up or down. If it's going down and it looks iffy by the time you get to Allentown, stop at a public charger for an hour or two to put a few dozen extra miles on. You shouldn't need a whole lot here, just enough to have a little margin for the last part of your run. If you have dual chargers, PlugShare shows The Sayre Mansion in Bethlehem has an 80A HPWC. They want $12 for it if you're not staying at the hotel, but an hour on that would give you an extra 60 rated miles and probably put you in good shape. The public J1772s are probably 30A good for 20MPH or so, not great but better than nothing. I'd take the time to thoroughly study PlugShare before you go to have an idea of what your options are, and make sure you can easily access it while on the go. (They have a good mobile app, definitely grab that.)
Please take the above with a gigantic grain of salt, as I'll be sitting at home warm while you make this trip and it's not going to be my butt on the line. And let us know how it goes!