I'll answer the Wallaceburg question first.
WAMBO (www.kent.net/wambo) is the W'burg Antique Motor Boat Outing, and it is on the second weekend in August. It is a pretty cool event -- antique boats, cars, fire trucks, a street dance, dance band on a raft in the middle of the Sydenham River in the centre of town. A lot of fun to go see, otherwise Wallaceburg is a pretty sleepy little town.
You can get to W'burg two ways -- from Algonac, just north of Walpole Island (the First Nation reservation) where the north and south channel branch from the St. Clair River, is the Chenal Ecarte. Travel down the Chenal until you get to the Sydenham River -- the Sydenham River will take you into Wallaceburg. It is deep water all the way, but you have to cruise at 8 kmh or less, as it is a no wake zone the entire way. It is charted - and depths at their shallowest are 6' most of the way.
There are a few bridges along the way -- they monitor 68, so you can call ahead and have them opened for you.
If you are on the southern end of LSC, you can also access the Chenal Ecarte where it empties into the lake (near Mitchell's Bay, ON)
Heading to Chatham, is about a three hour cruise up the Thames River from Lighthouse Cove / Radlin's Marina (again, no wake all the way, but most people don't bother) There is not a whole lot to do that is readily accessible from the downtown marina ... unfortunately Chatham's downtown has fallen victim to Wal-Mart and other big box retailers, so I can't even say that the stores are cool -- plus for better shopping it is easy to jump in a car and head to either Windsor/Detroit or London. There is some great old architecture in town, plus some historical references to the Underground Railway (think Harriet Beecher Stowe and Uncle Tom's Cabin) that can be found throughout Southwestern Ontario (including the real Uncle Tom's Cabin)
A word of caution ... with the rains that we have had in Southern Ontario this summer, ALWAYS be on the lookout for deadheads, particularly in the Thames and Sydenham rivers. They do not get reported on the Canadian Notmars on Ch 8.
Scott.