I plan my long trips in outline. I never go down to the level of booking hotels/campsites/breaks for each day but I do plan out my rough route. My trip to the USA in 2010 was a perfect example - I started with an idea, posted here for "local" opinions, got them, fed them into my plan and voila!
Plus, and maybe it's the nerd in me :), but I enjoyed the planning stage a hell of a lot :)
As for the GPS, I bloody love it :) I live a in (very) strange country and it's (the GPS) great for allowing me to ride off in the middle of no where and still be able to find my way home without carrying maps etc (I can't speak the local language either). Turn it off on the way out, turn it back on when you want to head home - awesome! :)
But that's me, it's the way I like to ride. I've known, and know, other bikers who ride more often, for longer, but with a greater degree of planning. They won't leave home without a hotel booked for every night and they have a bloody good time.
Each to their own and don't knock another person's life choices unless it impinges on your own.