OldMan, I am sorry to hear about your injury. I feel like close calls with older equipment is a regular for me sometimes when doing my farm work. Anyhow, I really do hope you heal up quickly and wish you my best.
As for the gas, the easiest way is to shut off petcock and run engine until it dies. That does a pretty good job of emptying the bowl. As for the tank, the easiest way would be to just pinch and remove fuel line from tank to carb and drain into a container for either reuse or preferably disposal.