see your map, my good man
its easy to reach from whiterun
just follow the road
I disagree with you there. Because of the massive cliff that runs along the route, the road that way requires you to go almost to Riften before doubling back. It is massively longer and more difficult. (Until you zoom in and tilt the world map quite a lot, the extent of that chasm is not really clear.)
The short way to get to Ivarstead is to go to Helgen, and then take the road East past Orphan Rock and Haemar's Shame through an easy mountain pass