When I was building Discover Alone I stayed in a hotel in London and found a hundred places within 200 metres I never knew existed. Your guests are the same. Put a small map on your website of everything within a short walk of your door: castles, ruins, holy wells, walks, the lot. Most of them free to visit.
Paste it anywhere on a page, the same way you'd add a YouTube video. It's free, there's no sign-up, and it keeps itself up to date as new places are added.
A page with a big QR code and the oldest places near you. Guests point their phone camera at it and the map opens.
Print my QR codeDiscover Alone has over a million places across Ireland and the UK. Made in Carndonagh, Donegal.