Are there going to be row boats for crossing lakes and rivers? Could you craft a row boat out of the wood from wood cutting? Also will there be a trust system involved with your horse granting bonuses to speed, stamina or strength/hit points or attack depending on experience. Would the same go for companions with a loyalty system and similar bonuses, will they be willing to take on more training. Can you buy saddle bags so your horse can carry stuff, different horses with different encumberences. Your can't ride horse back if it's already encumbered. Are there hitching posts in towns and settlements and stables.

Well about the companion part there's supposed to be a decent amount but they don't have as much depth as companions in fallout 3.

And regarding the mounts they haven't confirmed any yet.