Hire a guide, first day for walleye!!!! My family and my wife’s cousin and his family spent a week up there two years ago, roughly same time (late June). This lake is so big with so much structure that you need someone dialed in to show you where fish are at that particular time. Not even the spots the resort owner pointed out were productive. We had two boats going each day and caught one walleye the entire week.
What we did find were smallmouths but it still took a day or two to really get those down. Pitching jigs and plastic to large boulder areas was productive.
I also ran into some giant crappies and the largest pile of large gils I’ve seen. Target flooded timber in quiet bays for the crappie. You need to approach the wood very quietly and pitch small jigs-minnows under a bobber right next to the tree. I caught four fish over 1 lb. using this method.
For the gils, find a flat in 12-15 fow with deep water all around. Drop a plain hook, leech, under a slip bobber to the bottom right over the side of the boat. The leech will barely make it to the bottom if you’re in the right spot. We did this with the girls until they got tired of catching them, and the fish were NOT small!!
We stayed and fished in relative proximity to Vermillion Dam Lodge. Hope this helps!
Eric