Thanks for the reply!! We just left Moab on Tuesday morning (begrudgingly) and got home late last night.
We did end up hiking Corona Arch, but only made it to the part with the safety chains right before the ladder because my lab was too scared to climb up the face there - my aussie on the other hand was like a little mountain goat and ran right up it!! Later in the day we hiked Negro Bill Canyon which as you said was much better for the pups...they (especially Yukon the lab mix) had a ball with the water and sand...Mira magically turned from a blue merle aussie to a red dog in the span of a few hours

I actually like Negro Bill alot as well - there were only 2-3 other people I saw on the trail and it was quiet and really pretty - I would definitely hike it again.
I was really worried about their pads on the rock so I started doing Tuff Foot ASAP when I found out I was going, I kept an eye on them the whole time and didn't have any problems - their knowledge of cacti however could use some work - I don't know how many pokers I pulled out of Yukon!!!
What a great area (I spent a day in Moab and a day in Blanding) - next time I'll hopefully have more time to enjoy it!!
Stacey, Yukon and Mira