I'm not much help, but here are some places to consider:
My parents love The Granary in Eganville. I have memories of it from when I was younger and it was pretty tasty. But I personally have no idea if it still stands up:
I have had the pierogies (and the homemade mustard, but not together) from The Wilno Tavern and they are fabulous. Apparently much of the food is really tasty.