Thinking back, whenever I have bushwacked I walk at least half the route first to scout it out.  Then I know in advance if the route is do-able and where to navigate around the difficult spots. 
On Stumpy's 2010 challenge I was able to visit the area early in the spring when I could see through the forest easily, pick out a smooth route and become familiar with the terrain.  That was a fairly long portage which ended at the first of three lakes in a chain.  Between the small lakes was, in the nature of things, a string of fairly easy large animal trails that tended to follow the flat center of the draw, along an ancient drainage route between the lakes.