I used to live out there, growing up, and still get out that way every so often.
The swim: I've done several swims in Lake Wilderness. Water temps with a sleeveless wetsuit have never been a problem. Visibility in the water is good -- this lake is clearer than average for the area. You'll see a lot of trees on the bottom of the lake on the second stretch, but they're all deep enough to just make it a bit eerie, but no issue of contact. 7:00 am start? Sun won't be above the horizon, and there are a lot of trees around (plus a good ridge on the east side of the lake), so sun shouldn't be a problem.
The ride: Nothing in the way of long climbs, but plenty of little up-and-down that can break up your rhythm. But also plenty of long relatively flat sections to just settle in for a while. Road surfaces will vary from chip seal to smooth tarmac.
The run: Jeez... Talk about a boring run course. All MUP. The only real interruption to flat will be getting in/out of the park at the start/finish. Surface will be plenty smooth for road shoes. You're along a river for good portions of the course, which provides some scenic diversion, if that helps you, but there won't be much room for spectators -- you're gonna feel very alone on a lot of that course.
Good luck!
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