Uravan Launch
To run from the San Miguel and Dolores confluence to Gateway, you can start at Uravan. There are three bridges at Uravan. The downstream bridge is an old closed bridge. The downstream-west side might work depending on the water level (see center picture below). You have to drive upstream to the middle bridge to get to the other side of the old closed bridge. Launching at the old closed bridge probably depends on the water level. Picture below shows what it looks like at 400 cfs.
The second bridge, the middle bridge, has possibilities for a put in on the west and downstream side, but finding a place to park your car could be a problem. This area is a mining operation area. This bridge can be used to drive across the river and then you might want to drive along the river where you might find a good place to park and launch.
The upstream bridge was no good in April, 2006. There was heavy construction going on and the bridge was closed. When construction finishes, this might be a decent put in.
If you are willing to put in downstream of the canyon and hanging flume, there is a bridge across the Dolores just downstream of the hanging flume canyon. It looks to have an excellent launch and parking spot on the upstream and west side of the river. Unfortunately, this appears to be private property.Here's a of picture of the canyon you will miss by launching here.