How many rooms are there total? And is there a large area for a gathering of 20 people with room for a sit down dinner?

There's a perfect room for Gathering all 20 guests yes. It's a lovely stay, and meals are fabulous!

Not in the building we stayed in but they have two other facilities that are walkable and one has a larger space. Owners are awesome (very hands on) and I'm sure they would do whatever it takes to help you host your event. Might actually be better to have guests not all in one place in some circumstances.

6 or 7 rooms in the main house. But also 2 other houses. One has a dining room suitable for a small wedding or Rap Battle, etc. Wonderful spot. Bar next door so u can WaLk

Not sure on total rooms. But there is a hall for a gathering of over 20 people.