I went to Durango the last week of April 2007. The runoff was just beginning, but the fishing was good. It was a little slower on the Animas, so we drove over the mountain and fished the upper San Juan River, and it was lights out fantastic. I took a guided trip, and we fished big stonefly nymphs below indicators on 2X tippet. That was a first for me.
Regarding the locals, I stopped by Duranglers and was given completely the cold treatment. I picked up some tippet, indicators, and split shot while there and inquired about the fishing. I was told that my best bet was to buy some #24 midges and grit it out. However, when I ran into some locals that were fishing they were all having great success using these large stoneflies, and it was also the only nymph we used all day during my guided trip.
If you are looking for a guide I highly recommend you do a search for Animas Valley Anglers and Chris or Will can show you a fantastic time. Unfortunately, it sounds like your trip will coincide with the spring runoff in that area, so you may have to resort to fishing below Navajo Dam....
Durango still ranks among my all time favorite vacation destinations. I enjoyed absolutely everything about it.