If you're coming from Cambridge then Bewdley launch is the closest for you (Just north of the LCBO on Rice Lake Drive). It's a decent free public launch but since the town decided to revamp the area there is no parking for your trailer directly near the launch. There is free parking right at the launch but you would have to disconnect your trailer and park it in one of the spots (secured of course). A better place to launch is Harris Boat Works. Only another 5 minutes east at Gores landing. For $5 you can launch, park and take out. Beat deal around and a great launch.(You can launch before they're open on the Honour system, use the mail box at the launch) Don't use the public launch at Gores landing unless you like to swear a lot. One of the most frustrating launches I've ever used. No parking, no dock and very shallow.
As for fishing, if you launch at Harris you will see three islands straight north. Jigging or drifting on the north side of the channel between the western two islands over towards the mouth of the Otonabee river has been decent for walleye. The points off the island and the area just south of what's known as the "sunken islands" (see charts) have been decent fro smallmouth and for largemouth try your luck heading east from Harris (Gores Landing) to the first point on the southern shore. Just around the east side of the point there are some prime largemouth habitat. Hope that's enough to get you started. Enjoy.
Cheers