Hi,

I'm not up for the caravan as its about 1000 miles for me to Boston but I
have done the trip the whole way, from Columbia SC to Sydney Mines.  Took me
2 1/2 days.
You can get all the way to PEI with no ferry at all, via Calais and Moncton.
 There is now a bridge to the Island.
You can also get as far as Sydney NS with no ferry....or you can take the
expensive ferry from Bar Harbour to southern NS.
Personally I would recommend a couple of the trails in Nova Scotia on the way
up, especially Cabot Trail.   Also the road from Bangor Maine to Fredericton
NB, once you cross the border into Canada, is particularly scenic and its a
quick way to Moncton too.
Fabulous area,  wonderful change of pace !!

Good luck,  Steve