I also feel even a road trip you should plan to arrive a day early. On our first cruise out of LA we met a couple who had a BAD experiance. They were from Hawaii and had flown to La Vegas to visit her brother and leave their children in his care. On Sunday the day of the cruise they were headed to LA. Having lived in both CA and Las Vegas I know how backed up traffic is on the 15 with everyone returning from a weekend in Vegas. Before they even got out of Vegas they were in a car accident (her fault) totaling the rental car. They spent the next 2 hrs trying to get another car as no one wanted to rent to them. This is a 5 hr trip in good conditions. They said they made it in 4hr and 45 min and got to the ship with 10 minutes to spare. Lucky them! I wonderd why they did not go to the airport and then I remembered how the Vegas airport is on Sunday. No pre purchased ticket would mean no go!
On our last cruise in Nov there were 13 of us traveling from Orlando to Miami. Everyone opted to leave on Sunday morning and keep our fingers crossed. Some left at about 5am and were on the ship relaxing by the pool by noon. The rest of us who chose to drag their feet and not leave till 8:30 cut it close. I was in this group but since I was not driving I had to go with the flow. I was ready to leave at 6am.
We get to the port at about 2:00. We were dropped off and first vehicle left to go to the car rental. The next one contained my 8 yo grandson who on the way down had a crown fall out. My dear brother was asked to stop at a drug store and get a bonding kit to cement it back in. Off he went to do this task and return the rental car. My sister was in the first car and called to tell me that the roads were all tore up. All kinds of detours and no one answering the phones at the rental car company. Needless to say this very excited and happy person was now using some $#@!? words.
Well, if you are familiar with the Miami port area it is not really where you want to go looking for a store. It took my brother awhile to accomplish this task. Once done he also had fo endure the detours and closed roads. By this time it is 3pm. A shuttle to the port decides not to wait a minute for him and leaves. Another bus arrives in 15 min and the driver dissapears leaving passengers to sit on the bus for 15 min. Finally he arrives from taking his break. No taxis around. The driver enforms them that the first stop will be RCCL which sails at 5pm. My brother informs him that his ship leaves at 4pm but the driver did not care. There were 20 of us total but only 13 came from Orlando. Now 19 of us are on the ship getting ready for the muster drill not knowing if my brother will make it or not. Luckily he did and we all had a nice strong drink after the muster drill. Either leave really really early in the morning or leave the day before.