Finally got around to replacing the felt soles, followed the suggestions in this post, and the effort turned out well.

A word of caution--you will need an electric bench grinder (I borrowed one) and I had to buy an extra small can of contact cement as the amount provided in the kit bought from Cabela's was not enough.
The product description on Cabela's site did not mention that a grinder was needed, but the product instructions said so.

Yes, I'm aware that felt soles are on the way out, but I wanted to get a couple of seasons more out of these boots and I'm waiting for the bugs to be worked out in the new rubber soles. I've also read that rock snot can be tranferred from the tops of the boots, laces, and waders themselves, so the Lord only knows what changes we are in for.