Callibaetis and chrominids. If you've got a boat jigging can do well. Try near the hots springs if it's still cold.
You can probably find some more specific info if you check the caddis fly shop's blog archives, or google around a little bit. I haven't been in there in a long time but there's a great range of fish in there. My folks are going up there in a week or two but I doubt they'll fish, or at least try anything seriously or knowledgeably so they won't provide much of a report.