I made a trip out to Moab about a month ago. Arches is neat, but we didn't spend an entire day there at all. The lines were long, and there were way too many people at every pull off. This was a Thursday also. We came in through the main entrance, stopped at a few pull offs and then eventually decided we were going to do Tower Arch Trail, which is an off-road trail in Arches that takes you to Tower Arch. We saw one other person back here. This is a fun trail. Also, to avoid lines in Arches you can come in on Willow Springs Road, keep driving past the campground, and then the road gets a little rough and turns more into a trail. Then there's a fence with an opening saying you are entering Arches NP. You don't need to pay the $25 fee or wait in line. This is how we exited the park, I didn't know you could enter this way or I would have. From here you can take Eye of the Whale trail to Eye of the Whale arch and then this trail intersects with Tower Arch Trail. If you go left at the T it takes you to Tower Arch. Right takes you to a rocky hill climb which then leads to a smooth gravel road that takes you to the actual touristy part of the park.
Canyonlands is amazing, but you need permits for both day trips and overnight. Get these as soon as you can because they go quick. We camped at the very beginning of the trail and very end. The day in between campsites was very long but worth it.
TOTW is an awesome trail, but is starting to get torn up. It sounds like your truck is capable of it though. Fins n Things is super fun, with some incredibly steep parts that make you say "I gotta drive down that!"
Also, for easy trails with nice scenery check out Gemini Bridges and Long Canyon Road. Both only take an hour or two each, but they're fun. And a can't miss trail in my opinion is Onion Creek. It's got amazing scenery, 27 shallow creek crossings (Not sure if they'll be dry in August or not), and is just a fun trail. This is a trail you can do in a 2WD 4Runner most likely, its easy, but a lot of fun splashing through the creeks. Onion Creek isn't far from the TOTW trail head. When you are standing on TOTW you can actually see the Onion Creek trail running through the canyon.
It looks like you're from VA which is a long ways, just like I drove in from AL. My suggestion is to have a list/plan of lots of trails to run and things to do, this way if you end up with extra time you aren't fiddling around with trying to find something to do, instead you can just pick something and go. It's a long drive for us east cost people so we gotta make the most of it. You won't regret it!
Here's my trip report from my trip last month. There's lots and lots of pictures and decent descriptions of the trails. Maybe this'll help you understand what you're getting into out there.
Link to trip report in my build>>
http://www.toyota-4runner.org/3rd-gen-t4rs/208503-unners-build-2001-toyota-4runner-4x4-33.html