First, be sure to tie on an Adams at some point during your expedition for good karma--- it was invented for the Boardman and other rivers up there. Otherwise you could throw the universe out of whack.
Second, don’t forget the flies you already probably have. Some of these streams hold some very large browns, so stripping a black wooly bugger or big black marabou muddler thru pools or near logjams and under cut banks could pay off. General utility flies like a Partridge and Orange Soft Hackle wet fly are easy to fish (cast downstream and across and just let it swing) and are good to use as searching fly, and even during a hatch as an emerger (especially if there are caddis around). A Parachute Adams is often close enough to match a hatch as long as it’s the right size. And some grass hoppers (size 10) and ants (16) are always a good bet in summer
Here are some links you might find helpful. The Betsie is nearby too.
Fly Fishing the Jordan River in Michigan
Fly Fishing the Platte River in Michigan
Fly Fishing the Boardman River: description and fishing
Fly Fishing the Betsie River in Michigan
As far as specific hatches, Tie said it best. Your best bet is to stop in a local fly shop and pick up a few flies they recommend. And they’ll have the latest info on hatches that are coming off, and can probably point you in the right direction in terms of access to stretches that have been producing well. It’s money well spent. Your money, but still…
If you tie and wanted to get a head start, or pick up few flies in advance these are a few hatches you are apt to run into on these streams (and many others in the mid west and northeast so they won’t go to waste).
Personally, I’m a big fan of Comparaduns and Sparkle Duns, for dries but parachutes and traditionally hackled ones work too. I’ll leave off emergers, but the local shop can give you recommendations if they have been productive.
Baetis 18-20 (afternoons) (dries Blue Winged Olives, Parachute BWO. BWO
Sparkle Dun or BWO Comparadun. Nymph Bead head Pheasant Tail
Isonychia 12-14 (sporadic during day, evenings) This is a good sized mayfly, traditional dry is a Dun Variant. ISO Sparkle/Comparaduns are another option. Bead Head Prince Nymphs are a good imitation, but a local shop might suggest better ones.
Slate Wing Olive 16-18 (same as Baetis for dries in 16, but add a Rusty Spinner size 16 and BHPTN in size 16)
Trico 22-24 (mornings) (Dry: Trico Spinner. Since these are so small you’ll need 7x tippet too. Another option is to use a size 20 or 18 Griffiths Gnat. It’s designed to look like a cluster of Tricos and is easier to see and fish. And sometimes it works.. Don’t bother with a nymph for these.
Light Cahill 14-16 (evenings) (Dry: Light Cahill, Steno Sparkle/Comparadun. Nymph BH Gold Ribbed Hare’s Ear or shop recommendation)
Caddis 14-18 (afternoons) Dry Tan Elk Hair Caddis 14-18 with possibility of Little Black Caddis 16-18 and White Miller Caddis 14-16 this time of year. Emerger a size 16 Partridge and Orange Soft hackle, Orange Deep Sparkle (weighted) or Sparkle Pupa (unweighted).
Most of these hatches listed below are probably over by the end of July but ask when you get in town. I’d probably pick up a Hex or two and throw it anyway just in case you run into a big brown with long term memory.
Little Yellow Stonefly 12-14
Hex 6-8 (night)
Brown Drake 8-10
Yellow Drake 12-14
Golden Drake 8
Eastern Gray Drake 10-12
Good luck! Looking forward to the report!