I'll be honest, I can't recall how I unlocked the gloryhole for the barn, it just came up one day when I went to Caleb.
But what I did was just really raise his Like to me. (Oh and you have to have a Bottom Logan for this one, because I think he is the one who constructs the gloryholes... because he is now a slutty construction man, now that I think about it)
Honestly though, best advice is to visit him everyday and try to make him like you, flirt with him when he does.
After which I have done all of this is when the gloryhole scenes started.
EDIT:
For the Farmstead Gloryholes though... I also just made sure Ste liked me enough until the interaction to question the "holes" in the farm fences comes up (Plus making sure everyone survives in the Country Road questline- indicated as Green fonts in the Event Logs)