The last time I rode that boat it took about three minutes short of an hour to get from the French Quarter to Disney Downtown.
Why? Because the boat sat at the dock for a good while before taking off. Then it went to Riverside where it unloaded and loaded people. Then it went back to the French Quarter where it unloaded and loaded more people. Then, on the way to Downtown, it met another boat coming from Downtown and we had to wait while it got through a narrow place. (The captain cheerfully announced that boats coming from Downtown always had the right of way.) Argggggg ....
So, the total time from Port Orleans to Downtown Disney was about one hour. I was upset because I had a dinner reservation at one of the fine restaurants there, and almost missed it. But I didn't say anything.
Next time, I'll take a taxi. lol.
My advice ? Take the boat if you have plenty of time to spend, otherwise, skip it.
Enjoy.