Title says most of it. I'm driving from Colorado to Seattle and looking for a spot to crash for the night near Salt Lake. I'm taking 84 the whole way so somewhere close off of it would be ideal. Any camping near Thurston Peak area?
I think your title might be missing the target? Camping around "Salt Lake" for Big and Little Cottonwood Canyons is a common question and one which doesn't have great dirtbag options.
I believe you're really looking for a crash spot in the Morgan area? I'd change the title and I would imagine someone might have a tip for that. Personally, I'd probably pop off at Henefer and roll up Harris Canyon but I can't say if that is good or legal.
If yer coming on I80 to I84 you will be coming through Ogden not Salt Lake. Your best best would be the second Henefer exit then turn right which is the launch for boating lots off parking. The other option would be the two exits further at Taggert. Turn left this time and go under the freeway. This exit is the take out for boating. Both are probably fine or a dirt bag night. If you get further yer into Ogden and along the front side of the Wasatch which really do not have any good options except for the truck stops. If in that case I would press on towards Snowville and dirt bag around there cause then in the morning you can have breakfast at Molly's (just watch out for her Granddaughter).