Plotting my own route by freehand

This may have been posted before, if so - apologies.

I'm trying to plan a route using my own Start to Finish points but I find that I cannot complete the route back to the Start freehand.

I can certainly can start to create a return route and then I try to modify it by adding in "way points" where I want to go. I  get near to having success. But then the Map has ideas of it's own. It often deletes the route to the way point and/or plots its own return route via places I don't want. I suspect I'm doing something wrong, but what? Any suggestions would be welcome.

Just to reiterate. I know the route I want to plot - I just want to draw it freehand without intervention. Then create a pdf for my own use and friends.