Whether the roads are mototorways, main roads, minor roads or goat tracks it's relatively easy to plot a route along very specific roads from A to B or A to Z, via every letter in between. Having completed the plotting process, which only requires effort, you'll then have an excellent companion to guide you road by road and turn by turn, maybe over 100's of miles. Depending on how you have drawn your routes it will take you through cities or around them, right to every 'must do' view you have been told you mustn't miss and then right up to the front door of your hotel, all without you lifting a finger too often. I have just completed the creation of a complete lap of Germany, spaced over 15 days of travel and 'days off' to use in early September. I'm confident that it will guide us - down the roads I and not the device have chosen - with pinpoint accuracy on the last day just as well it will the first day and every day in between.
Bods will differ as to what software is best for plotting routes and to some degree or another which map sets might be better than others, but that's just semantics. Few if any of the many people who regularly use their devices to their full capabilities will say that they are shite for plotting entire holidays or lengthy distances, irrespective of the roads and destinations chosen.
Please could you throw some more light on why you are convinced that:
