If anyone can provide directions to Colonnade Arch I would be super stoked! GPS and basic road navigation is good. I will be coming from Crack canyon/Goblin valley-FYI Cheers!
Most roads are not labeled in the San Rafael desert so a GPS is recommended. A low clearance vehicle wont make it very far down the Keg Knoll road and if the roads are wet you may not make it out there with 4x4. The hike it self is pretty easy, last time I did it there was a quite a few cairns long the slick rock. You wont see the arch until your right on top of it so you need to approach from the south side to get underneath.
The road route is much more direct and has great views of the San Rafael Reef in the distance. I suggest doing that first then taking Nicks suggested lower route on the way back of if you're up for a lot more up/down and around the various domes and washes.