If you're generating that much, something is very wrong. And you certainly are not burning as efficiently as you think you are. I'm concerned that whatever you're doing is creating a lot of creosote buildup in your chimney. This is the cause of a lot of chimney fires.

95% of what you scoop out of your stove should be very fine ash dust. There should be very little charcoal.

Charcoal is simply wood that hasn't burned completely.

What is the moisture content of your wood? It should be below 20%. You can buy a moisture meter or you can borrow them from many local Vermont libraries.

Perhaps you're not burning hot enough. It's hard to know. I'd definitely find a knowledgeable friend or neighbor who can come to your place and see what you're doing in person.

20 gallons of ash and charcoal every 14 days is really concerning.