For the most part, the effect of streetwise skill is only noticeable if it is very low, i.e. less than 10, which the pc might have at the start of the game, but which will rapidly improve.
The pc is assumed to be jogging through town if on foot, or moving at normal trot speed if they have a horse/cart.
I'm not sure what you mean by that. By places of note do you mean inns/stores?Could places of note be marked on your map with higher streetwise?
I could potentially have a chance of ending the travel at some random point on the map if the pc has very low streetwise skill, but I'm not sure if the effort is worth the payoff.Low streetwise could have a chance of sending you to the wrong place, you got lost.