It was my great pleasure to be a part on your annual bbq and pool party. What a fabulous place, the food was great, and all members of family were just so lovely. I enjoyed meeting Allen's co-worker.

Thanks again for having us.

Be a part of... What should be capitalized. What a fabulous place! The food was great and you have a lovely family.
I'm confused about the co-worker part. Who is Allen?