We are here at the YC now and encountered this issue on Monday. We didn't see any boats and since I had developed a blister, we didn't want to walk that morning - its a nice walk but we didn't want to spend the steps. We took a cab and it was $10 with the tip.
We also had an 8 am breakfast at AK on Sunday, and I learned (from the front desk, bell desk and concierge) there is no longer a bus for early ADRs, and the bus doesn't begin to run until an hour before park opening. The last few years I have been here, at different resort hotels, there has always been a 6:30 bus. We drove to AK, but that's something to verify and keep in mind if you have early ADRs elsewhere.