How to start relationship with Caleb?
There are few events. One available if you in good terms with Bernard, if he let you stay for the night there will be dialog option to spent night with Caleb in the old barn. Walking option will open when you rise affection a bit (available only at night). Also later will be sex scene with few options and after you see it "Share beer" will randomly change to another version, where you play "Hide the bone" game with him ;) Also additional option available during the fair.