Mondays through Thursdays are good days for press conferences. Avoid the 10 AM news rush. Most press conferences are scheduled at that time. Keep your press kits simple. Offer phone interviews to no-shows.
Accessibility is related to timeliness.
They will remember you for the next time. If they cannot reach you within their time requirements, which may be anywhere from 15 minutes to two hours, they will remember that too, and eventually look to other organizations for a response. Chapters should leave a contact number for the press on their message machine. Preparedness should be balanced with accessibility. Never feel pressured to respond unless you are prepared.