I've thought long and hard about this. In my experience the most I can truly plan is set and setting. I can try to have my mind in a perfect place to just sit back and absorb the universe and end up having a total blast, not a truly relavent thought all night. Or on the other hand decide to eat a little and go enjoy a show or camp out with friends and end up having a totally spiritual experience. Sometimes I notice months later what a relevant trip I'd been on. Psychedelics have a bit of a sense of humor it seems.