Lake St Peter is ..ok smaller lake usually with above average traffic, though it does have lakers and smallies in it and an ice cream shop. If you don't mind the extra drive Barry's bay is nice, mostly a shopping stop though.
JohnBacon is spot on, the Madawaska art shop in Maynooth is worth the stop, and those butter tarts across the road are the best.
Eagles nest in Bancroft is nice for the sight, if you are thinking about stopping for lunch there is a small business in a converted house called "For the Halibut". This is by far the best fish you will ever eat, price is steep at $15 a plate for halibut, however I can eat with the best of them and I usually cannot finish the meal.
I havnet been to many of the others on your list, Paudash lake is on 28 and is a big lake, decent fishing but if you have a boat its a fun day on the water.
Burleigh falls is fun as well, you can take the kids and play in the "rapids"
Good burger joint on the 115 too, you have to park on the opposite side of the road and use the bridge to get to it but its good, pricey again but good.