I've walked it. It's about a mile and takes about 20-30 minutes (from CityWalk) just to get to I-Drive. Then add on however long it takes to get to your ultimate destination.
It's important to remember that you have to walk on Universal Blvd. There is no sidewalk along Kirkman Rd.
Author of "Universal Orlando: The Ultimate Guide to the Ultimate Theme Park Adventure" and
"The Other Orlando: What To Do When You've Done Disney & Universal""