I LOVE going to SLC for the quilt stores, and oh, yes, to see the Grandkids too! My favorites are:
Quilt Etc. 11 East Main Street, Sandy, UT 84070 801 255-2666. (corner of State and Main) This is south of SLC. Also in the southern part of the valley:
Fabric Center 9135 South Redwood Rd West Jordan, UT 84088
801 561-8726. They are somewhat more affordable than Quilt etc.
I have found better better fabrics even at Hancock, Walmart, etc than most other places. Lots of quilters in Utah! Have a great trip.