I have known Alice a long time, and probably TD would know better, but there is a sense she is really involved in making some key concept and maybe more importantly for Pete - editing of his concepts! I didn't get the sense that she was a hop on the tractor kind of gal.
Mrs. Dye was very closely involved with most of Pete's well-known projects between Crooked Stick in 1963 and Kiawah in the late 1980's - and maybe longer, but that's all I am sure about. On most of those projects the Dyes rented a house near the site and Pete would be out there 5-6 days a week.
At Long Cove, Alice would come out 2-3 times a week, usually at lunchtime, and check out anything new that was being done and provide feedback. She was NOT afraid to give feedback, and no matter what anybody on site was doing, there was a sense that it was not finished until Alice blessed it. The only green I know of at Long Cove where she really made "design" suggestions was the 15th. [When Ben Crenshaw came up the next year and picked his three favorite greens, Pete said afterward, "Well, I got one of them."]
And when I worked on the planning for PGA West, Alice would come into the office with Pete pretty often ... at which point we would have Pete, Alice, Lee Schmidt, Brian Curley and me in the room working on it ... and there was no question that her opinion on things was the most important to Pete.
As far as I know, Alice was not involved in the routing process, and for the most part she only "designed" a hole when Pete was stuck and looking for an idea. Also, as far as I know, she never took the lead role on any particular project. But there's no question that she could have if she wanted to -- and, to Ian's point, if someone would have hired her on her own.
There were two developers at Long Cove - Joe Webster, who had worked with Mr. Dye before, and a younger partner named David ?, who hadn't. At one point David worried what would happen if something happened to Pete, because they had no plans or anything to go by. Joe Webster told him to relax, in case of the worst Alice would finish the golf course and it would probably be better, and certainly less expensive.