Maryland Crossfire Group has a facebook page: Maryland Club

You can also try contacting PNA by sending him a personal message on this forum. Go to the Regional forums near the bottom of the home page and click on the Northeast Forum. You will find a thread there with the Maryland Club. Click on PNA post and a menu opens with "send a private message to PNA". Click on that and send your greeting.

About the antifreeze; the 50/50 dilutions you purchase at auto parts store are just fine for topping off your coolant system. However, it should be a hybrid organic acid (HOAT) type anti freeze like Zerex G05. It will have some silicates, and no phosphates. That's important. Don't use the older green formula product. I suspect the very new "Universal" anti freeze may be OK, but the recommendation is HOAT, G-05.