Originally posted by Knightframe:

Make a road. Its only usefull when you try to move a lot of ore in bulk and have no option to use a boat.

This here is the answer.

Roads are almost mandatory for comfortable cart usage. And as also mentioned leveling your run skill helps too.

Also, the cart can lead into hilarious situations. One of the best times we had on our server was when three of us tried to get a cart full of silver ore from the top of a mountain back to our base. Just getting it down the mountain in one piece was funny as hell.
And then when we ended up realising that the premade path we had going, from the base of the mountain through a black forest to our base, wasn't good enough it ended up with one of us trying to pull the cart along while two of us did our best to widen and even out the path infront.

It took a whole in game day but the amount of laughs that were had made it well worth it.