@Mike-And-Helen0 my guesthouse has a keypad, likely the guests will let themselves in,but my listing does specify acceptable hours of arrival.... I discuss all of this early and often and if anything seems fishy then I get more firm and may even meet them before I give them the code.
Just phrase it in your listing that you're looking out for them and their good experience rather than taking care of yourself.
"because of our rural location it is best that all first-time guests schedule to arrive between 4-9"
"we may meet you at arrival or if we're unavailable, we'll make sure you know all you need to to get your trip off to a great start"
etc etc