I plan a lot of multi-day trips in remote off-pavement areas of the southwest. Gas is often a major concern, so we need a plan that will maximize fun places to ride and get us back to gas. We also don't camp, so we need a motel and restaurant at the end of the day.
I often spend months planning a long ride. I read ride reports and investigate places of interest from as many sources as I can find.
But the reality is that the plan virtually never works as intended, so we have to be flexible.
But I don't like routes for many reasons. I always convert the routes to tracks and follow the tracks.
I will often create a special track when we are exploring an area on a day ride just to make sure I find the roads I want to explore.
But we often just go down roads and trails that we encounter to see what is there.