It depends on what you enjoy.
I like to plan my routes so that I don't end up on busy highways with no shoulders when a bit of research would have identified a country road going to the same place. It is easy to spot a road on a map that goes directly where you want only to find it is not suitable for bicycles when you get there.
If you prefer to "wing it," don't be surprised if you have to choose between a busy highway or a long alternative route that (always) goes over a steep mountain and adds dozens of miles to your day. That said, some of those alternative routes are the best ones!