Distance between two waypoints

I have a similar issue to Duncan where in some instances when I try to navigate to a waypoint on "Roads unsealed Track" (EOTopo Legend) the navigation path can be via the same designation track but nowhere near the shortest path as viewed on the map. Then to compound my problem, the last section will be 'as the crow flies' and designated as EOTopo legend "Nav clr" not following any shown track.
Example: I have set a waypoint at -31 36 43.27 116 11 4.03 (adjacent to Moondyne rapids picnic ground) and wish to travel from Perth. The route logged takes me via Toodyay road into the Avon Valley NP, along the railway line access road and across the Avon River!
What am I doing wrong? The shortest route is via Chittering Road.

If you know you want to go via Chittering Rd, add a waypoint for that. Here's what I get for your route:

Thanks Michelle.. I have that working and after a bit of practice now find it easy to use.

Thanks Michelle. Your screen shot only shows how to get part of the way to my desired destination. I had tried putting in multiple waypoints along the route (that I know well) but even then I still cannot get a route that follows the roads that are there. It still leaves me short of my destination with the last section shown as via a straight line through thick scrub (and I assume) by shanks pony!
This is a route that I know. The point of the query is, what about if I am in foreign territory where I do not know the country? Will the navigation ask me to cross rivers where no bridge exists or no cross-over exists? Will it indicate that I have to abandon my vehicle and take to foot?
I can do that without a GPS system and have a history of doing so.

Just received an email update from Exploroz Traveller News and hey presto, an answer to my query. It is a bit cumbersome but works! When all else fails - read the instruction manual!

Auto Routing
If you're already familiar with making nav plans and saving Treks (see User Manual instructions page 19-22), you may have come across times when a section of a track you wish to follow is not auto-routeable. Here's a simple hack to get around the issue:
Change the default MODE from Driving to Cycling then adjust the avg speed to a realistic driving value instead of accepting the provided cycling speed.