Just throwing this out there - Donkeys.
Equip a rope and tame a wild donkey, the way you would a cow or sheep.
A donkey can carry 4 large items, same as a cart (baskets, chests etc).
Leading a donkey by a rope, you can move at WALK SPEED through the forest tiles (as opposed to crawl speed with carts)
Maybe donkeys can enter a boat, and count as the second passenger?
Donkeys eat seeds and straw, and while away from the trough you can equip a seedbag to the donkey's neck for it to eat from.
Not sure about eating donkey meat though, I did a little googling and apparently donkey meat is eaten in China and some parts of Africa.
Having a domesticated animal like this could make trade and mass resource gathering easier, for example if I wanted to meet someone at RoB with a hundred chantrelles or so - or if all of the trees by my house were chopped down, I could make one trip out to the remaining forest and load him up, as opposed to several trips lifting logs, or one godawful slow trip with a cart.