Had my current camper for 15 years now and probably every trip i have done has been spontaneous , only truly planned trips have been Switzerland and Australia.
Durness and Sutherland are my favorite long distance trips but then i am happy to travel 40 to 60 miles for a couple of nights, means i get to spend more time playing in the hills.
Best thing is i can avoid hotels BBs etc and therefore don`t have to sleep in a bed that a complete stranger has not long vacated (just one of my phobia`s).
Another plus is I run the van on LPG which is half the price of petrol and helps to make economic sense of camper ownership.