I have watched every episode of Bones, and apparently one of them was a crossover episode with Sleepy Hollow where the story was continued in Sleepy Hollow. I would like to watch the second part of this story, but I'd rather not have to catch up with the preceding 2 1/2 seasons of Sleepy Hollow. Can I just skip to the Bones episode in Season 3, or do I need loads of knowledge from preceding seasons?
I watch both shows and have seen both parts of the crossover, you probably can watch it without seeing the previously shown Sleepy Hollow episodes as long as you at least know the rough premise of SH as it was (from what I can tell) intended to act as a way of attracting Bones fans to Sleepy Hollow so while it forms part of the arc for season three it's accessible without knowing that.
To be honest though if you just want to watch it for the Bones angle I'm not sure I'd bother unless you're a completionist, it's certainly not the greatest from a Bones perspective.