Ditto what MM and MT said :thumbup
My trips have mostly been in this time frame.
2013 Walleye opener is still the 3rd Sat in May(18), so to be legal you will have to do with Lakers/NP and I think SMB?

Good news is the Lakers are in shallow and the NP should be too. Conditions permitting, I'd be trolling a couple of lures out of each canoe, different depths/styles anytime your on the water.
If your worried about losing expensive lures or don't want to deal with snags/retrieving expensive tackle, tie on some yellow/white 1/4-3/8 jigs with the same color Twister tails.
I've caught the Grand Slam before on that set-up and I'm sure others have as well.
Along with good rain gear, a couple of decent tarps won't hurt either.