I am aware beefalos are already able to do this, but only with a player riding them, here is the thing:
Some months ago chester wasnt able to "pathfind" between boats (there isnt really boat pathfind because its just go from A to B) but basically chester was able to jump to a boat that was close to his location, and the same for land.
But for beefalo, if you desmount one in a boat and then run to land with the bell, the beefalo tries to get to you but he cant, even when he clearly can jump the water gap, so you have to mount it in the boat and move it to land
Maybe buff its AI so he works like chester?