The main resource you have is the experience of people who may have done it before, particularly Baronial officers. Never be afraid to ask, whether directly or on the discussion list!
The Barony has a quantity of gear that is available for use by event stewards. Please contact the Quartermaster well before the event with a list of what you need and arrange a mutually convenient time to come and get them.
In addition to the above, if the Baron and Baroness will be present, you would normally expect them to bring the Thrones, kneeling cushions and other thing that make up the Baronial Presence, as well as the Baronial Pavilion and associated banners and paraphernalia — though there are plenty more banners in the inventory.
And it never hurts to ask around, whether via the email lists or directly. Many of our populace have personal banners and other items which help decorate venues or make events run more smoothly. Though they may bring them along without prompting, a clear call will increase the chances.