Marijuana is not "decriminalized" in New York.

Marijuana for medical purposes is nowhere near legal in New York State, and I have never heard even a rumor of the existence of anything resembling medical dispensaries. Many people are arrested daily for it, even for possession or sale of small amounts. The prices here, if you're lucky enough to find any at all, are about as high as anywhere, and one of the main reasons for this is the laws.

But, if you insist on trying your plan, good luck - and I mean that!