Traffic couldn't get hairy once you get within a couple miles of the stadium coming out of Provo Canyon. Just come early and there won't be an issue. Parking can be had in a variety of areas, free on campus in certain lots, reserved in the lots next to the stadium. Streets around the stadium as long as you're early enough are free. There are a bunch of paid private lots at people's houses/businesses where you can pay about $5-10 on game days.

Sunset is 6:47 for game day, so after the game should be over. Jacket weather, but extended forecast shows a nice day, so not bad football weather at all.