I agree that this sounds like a pet project for you, which again is totally fine if you are okay with spending your money in that way.
To me, the STR market (and from what I hear about the smokies) is on a downward trend. This year might not be the best year to go all in with an investment if the sole goal is cash flow or appreciation (not personal use).
In a mature market such as the smokies, I think you can reasonably arrive at a fairly narrow occupancy rate. For arguments sake, suppose it's 65-75% given the market occupancy, the smaller size, and the newness. So that's 21 days/mo.
I'm NOT an expert on the smokies market, but lets say this thing costs you $600K all in, you put 20% down, and with utilities and OTA fees you are all in at $4,500 - $5,000/mo. That means you need to average a nightly rate without the cleaning fees of $240 on a small cabin. Sounds high to me unless you are able to really make this unique.
I realize I made of lot of back of the napkin assumptions above, but it sounds like a no go to me.