@Christine0 And Paul,
Your cabin is beautiful!
There aren't any tricks or things you can do on your own to make your listing appear if it isn't on the map.
However, that doesn't mean there is nothing to be done.
The main issue is this: if a listing isn't in the area currently showing on the map, the listing cannot appear in the search results.
Since you can't physically move your cabin, you have to move the map (so to speak).
When a guest searches for "Walker, MN" the Airbnb system determines what area the map will show initially. Well, actually someone at Airbnb probably had to decide where to center the map and how much area to show. Apparently, the initial map for Walker, MN shows too small of an area. Only 22 listings are on the initial map.
If the initial map were zoomed out even just one step, it still only shows 39 listings, but would include your cabin.
You can try to contact Airbnb support and ask if you can put in a request to have the initial map for Walker, MN to include a wider area. Say the initial map only shows 22 listings, and that even one step out would still only show 39 listings (which is very reasonable). Tell them to please include Garfield Lake.
There is no guarantee they can/will help you, but that is what you need.
For Colleen and Ross: your problem is the same, but different. You are also outside the initial map (but for Knoxville). However, the initial map for Knoxville already includes 300+ listings, so there is very little incentive for Airbnb to change what the map shows when starting a search for Knoxville. You can also make the request, but I am not sure how it would be received