I was the TL on a Main Salmon trip last July, took two of my kids, and a fun group, and would go back in a heartbeat. Beautiful river and camps, great rapids, fun but not scary. Hmmm, maybe you want another rafter?
Snake is fun with a few big rapids but IMO not the same wilderness trip as the Main. You can also consider a jet up or jet back for your shuttle and get to see the river from the upstream perspective. Takes about 4 hours that took you 6 days to get down. The price, assuming you fill the boat up, isn't all that much more than the car shuttles, minus the 600 mile trip plus gas on your truck and trailer, and the trip back via Riggins.
PS. I have lots of info to share from our trip if you head to the Main. Have fun.