You get it as a pony from Barley and it takes 120 days to mature to a horse that you can ride or use its saddle bags when harvesting crops, instead of the basket.
Unfortunatly, your horse will often move right when you want to throw a crop in, so he's not that wonderful. They should let you at least ride him to the south, in the wild mountain areas.
the cart idea would be a cool feature as it would be like 2 times ur usual walking speed at least and you could use it to transport you, ur son and ur wife to festivals the shops etc etc etc
but they should sell it for a bit of money so it takes sometime to get it and you should make it out of wood and get it from gotz for like
500 pieces of lumber (they always go a bit ott)
5,000G and you should have to leave him for a little while and he shgould deliever it to the space next to da stable...
I like the boat from HMGB3. The cart/wagon sounds good too. I just wish you can travel around with your wife too if you wanted to go fishing or travel in the wagon to a different town with her and she'd say different things along the way. Just wishful thinking..........ehehe