Lodore is sweet. You float thru Lodore canyon, echo park, whirlpool canyon, rainbow park and split mt. So its like going on 5 trips. The actual Lodore canyon is only aboit 20 miles long, if it were 200 it would be as popular as the Grand.
Deso is nice, easy to get permit, camp anywhere , on right.
Dolores is great if you can get water. You float thru ponderosa canyon, box elder canyon, little glen canyon then slickrock canyon, lots of diversity.