Each state has its own marijuana laws but the reasoning behind the answer makes sense- if using marijuana or cannabis-derived products is legal in the state where you are. (So check first!)
Is it legal to smoke marijuana — or drink a beer — in an RV if you are living in it?
If you live in an RV and use cannabis or alcohol, is it legal to use to drink a beer or use marijuana while your home in Washington state or are you in danger of getting a DUI?