After crossing, you can have a snack and rest and then either return on the ferry, or take Quebec route 148 back to Aylmer and Hull, returning to Ottawa across the Champlain Bridge.
I generally take the Carp Road, through the town of Carp, and enjoy the twisty S-curves just North of the town.
Continue North on this road. When you get to a stop sign at the first intersection (with a township office and police station on your right) proceed straight through and keep going North.
At the next stop sign (road 22), turn right. A couple of kilometres down you’ll see a sign for a left turn marked “Ferry” and “Quebec”. Take that.
Single-rider motorcycles were $6 on the Ferry the last time I was across.