Dex, a connection with nature IS a connection with yourself, as you will find out if you try peyote for example. You'll see that you are everything and everything is you, I am you and you are me, there is no meaningful difference and there is no problem anymore with being with other people, b/c we're all the same. These are the kinds of things I have felt reinforced by san pedro experiences. That's the plant I would recommend the most out of all you mentioned, it literally changed my life in tangible ways, and the positive effects have lasted for weeks on end for me.

However, no psychoactive in itself does all the work for you. You should read up not only on drugs, but on meditation, buddhism, Zen, Taoism, Sufism, etc--all types of mysticism, try taking a good class sometime or reading a book that combines spirituality AND drugs insightfully and intelligently--like The Marriage of the Sun and the Moon by Andrew Weil. The simplest and most important meditation practice, which should be 'easy' but can take a lifetime, is learning not to judge yourself. Psychoactives help immeasurably with this, as well as the ability to let go of thoughts.

Nexus, OF COURSE marijuana has the potential for aiding in spiritual growth. Just try smoking it alone, if you've never done so, and hopefully see what I mean. I don't know of any other readily available plant that has helped me more in developing my healthiest attitudes towards life and my spiritual outlook. It's a really versatile plant (like any of the psychedelics) so you can use it for any purposes you choose--if you think it's going to be spiritual, it probably will; if you think it's gonna make you silly and laugh with your friends, it probably will (sometimes both at once). Rastafarians have long used it for meditation practice. I think pot just helps you to be yourself, pure and simple--and what could be more spiritual?

You should also ask yourself what you think you MEAN by the word "spiritual," since I think it's a term people use vaguely, and it doesn't always have much substance. What do you want to get out of life, in a really big sense? What do you need in order for it all to seem worthwhile to you? How do you want to live your life? Psychedelics have the potential to put you back on your feet and restore love for all beings to your heart (P.S. to those who thought otherwise... LSD is definitely no exception).

So yeah... try Peruvian torch cactus, it's the easiest to get w/o going through dealers since it's a LEGAL entheogen (usually sold as "incense" in this country). You WON'T be disappointed.