Not fly fishing only, just artificial, single/barbless lures. A buzz bomb will work - especially after the opener - they'll hit anything then. Just watch out for snags. The lake is full of submerged stumps.

Also try spoons and spinners. Also, before I tried real fly fishing, I did very well with flies (both wet and dry) on my spinning rod. Just get one of those clear bobbers and use 4 or 5 feet of leader to a wooly bugger or dry fly. Slow retrieve - letting the wooly bugger rise and slowly sink works great. For the dry, just cast out and reel in a little to get the bobber away from the fly. If no takers, work it in a little. If it sinks, no problem, just work it back in like it was a wet fly - sometimes that works best.
This is a great way to fish the alpine lakes as well. Sometimes you have no room for a back cast - and a float tube can be a hassle to pack - so a spinning rod, bobber, and some flies works wonders. My favorite method for alpine brookies...

Good luck!