My suggestion is a product that I have used for many years and is now freeware! It started as a piece of route planning software for 'Bikers' and allows you to drag routes to fit a specific 'tour or drive' which I found very intuitive. The early version called Tyre to Travel continues as a Windows based product and you can dowload compatible SatNav files for several GPS manufacturers. There was a 'split' in the development and one of the developers (I think) has taken the product - 'MyRoute App' into Apple as well as Windows and even offers an App on Iphone's etc. so may be a better fit. It is a subscribe service.
This link takes you to a page that describes the two versions and again I can only praise the original version (now free) and seems to continue to develop.
Link to TYRE software description 
