We haven't had real heat problems for several years now. It has not topped 80 more than a few times in years. I'm not sure there is ever a time where there are not a ton of miserable little bugs. I discover annoying new insect life nearly every year. Just when I think I've experianced every horrible insect attack possible, we get a gigantic hatch of some horrible bug I've never seen before. Bring Deet. I'd plan the trip for the best time to fish. Spring up here is incredible. Go at least a week or two after opener, because opener about half the time this far North can be a snowy miserable mess. Or like 2 out of the last 3 years, still have ice on the lakes. The Smallies will still be shallow, and so will the Pike and Walleye. By your time table, make it June 1st. I'd still bring warm clothes. You can find guides around, check out the Ely yellow pages, but a good map, GPS and a little study will do you as much good as a guide. If you are thinking of trout fishing there, a guy named Shawn Perich wrote a book that has a bunch of fly patterns for the area, and good info on trout fishing there. I think it was called flies of the arrowhead. I found a site for him, but not the book. it has a contact spot.
North Shore Press: Hovland Minnesota Book Publisher