You have several options. In my opinion here they are in order from most desirable to least.
1. Fill up your outboard tank with 50:1 Gas:TCW3, put some sta-bil in it and use it next spring. This is what I do, it works great. Best to leave it in a place that doesn't see huge fluctuations in temperature, just about any building will do as long as it has 4 walls and a roof. I've put gas like this in an attached garage that stays around 40 degrees in the winter, 80 in the summer, it was fine 18 months later.
2. Put it in the tank for any 4 stroke non-fuel-injected small engine that you will use during the winter (snow blower is a good choice if you have one). It will smoke a little but it will do no harm to the motor, very important to make sure it's NOT fuel injected though. Alternatively, you could put it in a 2 cycle engine as long as it also takes 50:1. I would avoid putting it in any 2 cycle that doesn't take 50:1.
3. Put it in the tank of a any non-diesel non-fuel-injected car or truck (under no circumstances put oiled gas in anything with fuel injection, it could ruin the injectors). It would possibly be safe in a diesel motor but I'd worry about it ruining the glow plugs. In my opinion not worth the risk.
4. Use it to start a bonfire, or several smaller fires.
5. Pour it on the ground to kill weeds (probably rule this one out since you're hoping for an eco-friendly approach).