Plan to hire a taxi for the ride to the park ($16 each way) . You can get the taxi number online, make a reservation. When you come off the boat gangway the Taxis are to the left. See if the dive guide will meet you exactly at 8AM when the air cart opens at the park. Pay the extra to rent a steel HP-100 tank, that is the SoCal standard. Bring cash to make the transactions quicker. If you really watch your time you could get two dives in but it will be very tight. If you are renting all your gear in Avalon it is probably unlikely you could make two dives as the gear fitting will take 45 mins. But if you bring your own gear except for tanks and weights you could make two dives if you jam. Depending on your mainland schedule you could rent all your gear in LA and take it out to Catalina. Suit Up 8:00-8:30 , Dive 1; 8:30-9:30, one hour surface interval, Dive 2 10:30-11:30. Strip off/load gear 11:30-12:00. Ask the Guide to include the wreck of the Sujac in your tour. Remember you cannot fly until the next day (18-24 hours depending on which guideline you follow). Pack some water and a few energy bars. A small ground sheet is really handy to throw down on the ground to keep your gear out of the dirt. Buy a cheep painters drop cloth and throw it away when you are done. Some people prefer to gear up next to the seawall, I like using one of the benches around the exterior of the Casino. Remember your C-card. The Park is worth this effort, especially if the viz is decent.