I have rafted as part of a number of tours.
The Sevylor I have weighs in at about 28 lbs with all the extra gear.
(That's a lot of extra pounds and tough to ride with.)
I would ship the raft to the nearest post office.
Then I would struggle under all the weight to get to my put-in.
(Oh - - - I also carried a big inner tube to strap the bike onto.)

Once I was on the river I probably looked like the Beverly Hillbillies.
But it was sweet - and I could camp on quiet river islands, etc.
I had me and all my gear on the raft.
And I trailed the inner tube with my bike strapped to it.
Obviously, I was not set up for anything remotely technical.

I think it cost me $25 each way for postage - so the outing was $50 extra.
I've done parts of the Missouri and Yellowstone Rivers.
In both these cases, I spend a few days on the river.

Can't remember the river crossing in Alberta.
Really, $50 and the time to set up is pricey for what amounts to ferry ride.
But it allowed me to ride on super quiet back roads.

Actually, it's easier and cheaper to hitch-hike across rivers.
You ride to a moderately popular put-in.
Then pull your sign out with a big thumb.
Sometimes it's only 5-10 minutes - other times an hour or two.
But I always have gotten across the river.
Done it on the Columbia, Mississippi, Potomac and a few others.