Don't forget a good Tripod and meter! Note papers and pencils, I would suggest to bring along a favorite backup camera just in case you get frustrated your LF. As you filters, Use what you have even if you have to hold it over the lens.
Most of all. Have fun at the workshop! You will be around fellow photographers who have a strong interest in exploring LF photography. Share your images and share with those who brought images. That's whats great about Apug. Its like a 24/7 photo workshop!