Ideally, I would like to do it at home, in my own bed, with my beloved dogs next to me. But I don't want to upset or traumatize my pups (also don't want them feasting on my remains, lol). Plus my best friend/neighbor would probably find my body or at least have to live next to where it happened.
So ultimately I probably would do it at the crappy local motel down the road where addicts frequently overdose. Motel staff and local cops are pretty used to guests leaving in body bags so it will be business as usual for them.