I have not been on the Explorer but I have been on two of its twin sister ship's the Adventure of the Seas and the Mariner of the Seas. And I have been on many RC cruises. You will not have any problems on ship, either getting on or off. Many of the cruises that I have been on have had handicapped people in wheel chairs and motorized chairs. There is handicapped access all over the ship and it may even have a lift to help him into/out of the pool. There are multiple elevator
bays on the ships and so he can have access to all decks and activities.

The ship's staff will assist him getting on and off the ship. In St Thomas and San Juan the ship docks at a port and uses a ramp that he can roll up/down, maybe with a little assistance. In Labadee the ship will stop for an all-day beach party and must use a tender boat to get from ship to shore. But the ship's staff will assist him in getting off. Also, I know that they do have special wheel chairs for the sand on that island. The chairs have extra large balloon tire wheels that roll very well in the sand. So he will be able to get around on that island. Labadee is a rather large place and they do have a tram that will take you from one location to another. I am not sure if it will accommodate the wheel chair, but there are porters on the island who can push him around if that's what you prefer.

I have not been to the other port stop you mentioned. I suggest that you call the cruise line and make sure that they know that you will need assistance at certain points on the cruise. Below are some more general tips for cruising; based on the many I have done.

- Its best to pack using soft-sided luggage because with space limited in your cabin it fits under the beds better if its not hard sided luggage.

- Pack using the vacuum clothing bags (about $20 for 3 at Target) so that you can get more in your bag AND so that if the TSA at the airport opens your bag they can see what's inside without rummaging through your things.

-Take a small carry-on bag for the last night of the cruise. On the last evening you will be required to put your luggage outside your cabin by about 2:00 AM so that they can start taking it down to the lower deck for offloading the next morning. So you will need a small bag for your toiletries and your clothes that you sleep in.

- If you can take a six-pack of bottled water and soft drinks in your carry-on for your cabin. You will have to pay for both on the ship and its nice to have those handy in the cabin.

- If you are taking your cell phone, MP3 player or other item that needs to be plugged in take an extension cord as the plugs in the cabin are generally not in the best places and there are usually only one or two.

- Take a small bottle of hand sanitizer and/or hand-wipes. There are generally sanitizer dispensers at the entrances of restaurants, the buffets and dining room, but some times the are not there or not working. The sanitizer helps prevent the spread of the Norwalk Virus that sometimes occur on cruise ships.

-If you plan to get into the pools or hot tub as soon as you get on ship (they will be open), bring those clothes in your carry on bag; you other luggage may not get to your cabin until much later in the afternoon.

- Take a can of air freshener for your cabin bathroom. The bathrooms do not have exhaust fans.

- Take a few zip lock bags of various sizes; they always come in handy.

- Take some one dollar bills (also maybe a few $5's) for tipping the porters in the airport, at the pier (they do not work for the ship), and the small bills will come in handy in port stops for buying small items in the markets and at vendor stands; especially bartering places.