The original poster didn't say anything about his dad's health/age. The San Juan, below the dam, can be pretty tough wading. Lots of moss and slime. We've waded some there, but for the most part, floated it with a guide.
I would disagree with an earlier post though; not much dry fishing on the San Juan. Primarily tiny nymphs on 5x or 6x tippet. Occaisionally some dry action, and folks anxiously await the "ant drop" feeding frenzy each summer.
On a personal note, we've haven't been to the SJ for several years, and I'm not sure we'll go back. Don't get me wrong, its an incredible fisherie, but its not the real world. When you catch the number and size of fish that you can at the SJ, it can set you up for disappointment when you go elsewhere, if you don't keep things in perspective.
Our more recent trips have been more focused on dry action, and we've fished the Yellowstone in Paradise Valley near Livingston, MT, the waters in Yellowstone NP, the lower Madison, the Elk River in BC. My wife and I leave for Esquel, Argentina, on March 5 for our first trip to Patagonia. My son and I are going back to MT this summer and will fish the Madison and the Yellowstone and the fish around Missoula, before we head home.
[This message has been edited by One-Eyed Fat Man (edited 2/24/2008 9:59a).]