Either way Deer Valley and especially Alta are pretty epic resorts especially if you take into account their access to the local backcountry.
Now that I'm getting familiar with the SLC\Park city area I'm astounded by how close all these resorts actually are to each other. One can easily skin from one resort to another and ride some pretty kick ass backcountry area on the way.
As long as you're on skis, I think there is a program you can sign up for that does exactly that - it's basically a mini tour that goes from one mountain to another or something, I remember reading about it.
Of course, if you're an experienced BC rider with a split, there's really no need to pay for that schmooz you can just do the same thing on your own.