LSD + ketamine is meant to be a very good combination-make sure tou have plateued on the acid then dose with ketamine-as for the E don't bother-your putting too much strain on your brain, and you will be tripping too much to benefit from the euphoria.

Weed is always good with psychedelics, but again I think you will find it a lot of effort to smoke while you're on K.

Also LSD + weed is a very good combination-known as candyflipping. I would choose either of these combinations, not all at once though.