The Rideau upriver from Merrickville is worth exploring: lots of wildlife sightings, photo ops, and barren shorelines. The south shore from Merrickville west towards Kilmarnock is a bird sanctuary, so it is totally undeveloped.
The river opens up to a wide expanse to the south as it takes you to Jasper. You can spend a lot of time exploring the southern area. If you go straight to Kilmarnock, you’ll get there in less than three hours. Parks Canada has a washroom there, but there are no other facilities, so pack a lunch and bring beverages. Kilmarnock is quiet and scenic, and a great location for a quiet picnic.
There is no public land where you can beach your boat, except for two public boat launch sites on the north shore.
Bring your camera and a dry bag. You’ll see shorebirds, herons, loons, muskrats, ducks, and more.