If you know what region you want to go to, look for a local tourism bureau website. Its often good enough these days and usually has offers from locals
Wuppertal, Solingen, Remscheid, 3 German cities in the Bergisches Land who are host to a large density of toolmakers that often still handcraft with 100year old machines
Next next step These Services must offer Public APIs for third Party Provider to Connect. Imagine a Europe wide train booking Site or similar