Try Kiwanis Oceanfront Camping in St. Andrews. The sites are a little tight but not bad. If you ask for ocean front the sites are drive-in, back-out so your big front windows have an unrestricted view of the Bay of Fundy. Lots of room to deal with the toad in the parking area near the office.
If you are in the Fredericton area Hartt Island Camping Resort is set up for big rigs. Long pull through sites, level and fully serviced. This is on the banks of the Saint John River.
In the Halifax NS area try Shubie Park. It is a municipal campground. They have a few big rig pull through sites so be sure to reserve in advance and specify what you want. Only downside is no sewer service on sites so you have to dump on the way out.
