Pretty much anything outdoors is enjoyable while tripping:
Cycling is always a good experience (as long as my vision isn't too distorted and the resulting type of visuals themselves.) Mountain biking is the most fun, but I'll stick to bike paths and fire roads if I have heavier visuals, but trails are amazing to ride tripping with relatively my vision intact.
Fishing, especially fly fishing can be great under the influence of a psychedelic. Wading with a fly rod is especially cool. Casting jigs and jerkbaits for bass and walleye is cool too, especially when you get on a good bite. Whenever I fish for bass or walleye, my catfish rod always has a line in the water.
Hiking, in my experience, is the outdoor activity that is most accessible activity for me and the people I know trip with those under the influence of psychedelics.
Swimming is simply amazing while tripping, so long as it's done with the utmost care and with safety measures taken.