there are many jobs that foreigners cannot do and farming is one of them. Growing cannabis would fall under that. Opening a coffee shop, doable. But who knows what Thais will do with cannabis laws… They might totally change next year.
not at all. As Craig suggested below, do a Thai language course. It will only benefit you while living in country anyway. You will lower your monthly outgoings by 75%, compared to living in the US. Save up for your elite visa and enjoy Thailand 👍