Some notes - the best dispersed camping outside of Moab is along the Gemini Bridges road, north of Moab, or along the Behind The Reef road (not trail), specifically at Prostitute Butte, south of Moab. Bring a portable toilet system - it's required for Parkland like the White Rim, and it's required on some BLM land too.
Picking up your boy in SLC - there is some wheeling in the mountains east of the city, but they're snowed in this time of year and gated or groomed for snowmobiles. There's lots of wheeling in the desert to the west of the city, I can recommend some cool spots if you're into western railroad/mining history. If you're just looking for scenery and mildly technical trails, the Swell is where you wanna be. Eagle Canyon is good, Devil's Racetrack and Fixit Pass are right in the same area and a step up in difficulty if you want. Goblin Valley is cool. There's rock art and old uranium mines everywhere if that's your speed. The MK Tunnels are a neat piece of Cold War history.
White Rim is super. You didn't mention if you'd gotten campsite reservations yet, do that now if you haven't already. This time of year there might not be anything left if you wait and get your permits at the ranger station. Top Of The World is a great trail, if you're ready for some decent ledge action. If I remember right you're lifted on 32s, is that right? That should be enough truck, as long as you know where to point it

. Combine it with Onion Creek to add some great scenic driving to the day.
On your trip back from Moab area to SLC you could explore more of the Swell, or check out old coal mines and ghost towns around Price and Helper, or drive up Diamond Fork off of US6 and maybe find some snow, lots of options.
Hit me up when you're in town. If I'm free I'll come play for a bit.