Even though the class may be full, if you show up there is a good chance that they'll let you in. Good luck. BTW, Billerica just started and they may let him in even though he missed the first class. I took mine there and they were very flexible.
Maine does a lot of the classes that are just one evening plus a full weekend day a week-and-a-half later, with independent study in between. (This is offered occasionally in Mass., too, but rarely.) There's an option in NH to do the studying part of the course online and then just spend one day doing fieldwork, which is even faster in theory but they fill up really fast.