Having come south from Vermont for more late season play on the water, and with a few hours but no company, I chose to paddle Breton Bay. I put in at the Camp Calvert Landing, just east of the Leonardtown Wharf Public Park, and paddled the eastern shore of the bay down to Abell's Wharf Landing (public boat launch with ramp and dock, but portapotty gone by the end of October!) and back.
There were several marshy areas along the way, and one spectacular Great Blue Heron - largest I've seen in years - that didn't see me drifting by until I was within about 20' - then took off. I didn't have the camera out, and didn't dare move for it, so the picture is still only in my head.
There are lots of houses - not a wilderness experience - but this time of year there was no one else on the water the entire three hours I was out, although I'm sure that during the season that's not the case!
On my list is to paddle from Port of Leonardtown Park down to the Wharf at the foot of downtown Leonardtown, but if there's current I'd rather not have to paddle back up, so want to have a car at each end.
Camp Calvert Landing has a couple of picnic tables and a small sandy area from which to launch. There is only room for about three cars. Abell's Wharf has full trailering facilities, ramp, portapotty in season, dock, lots of parking.
Route 5 (Point Lookout Road) to Camp Calvert Rd. to end. To Abell's Wharf Landing: South on Rte. 5, right on 244, right on Breton Beach Rd, right on Abells Wharf Rd. to end.
Water Trails in Western St. Mary's County, available at welcome/info centers