Merc,

There are 2 airports you need travel from. Belize City to San Pedro. I prefer to fly right away and get my feet in the sand. As Marty said there are ferry's in Belize City but you have to taxi to them & arrange times & hope there is room. Don't know if all are covererd or if some are still open boats where things can get wet on the long ride. The water boat & taxi maybe cheaper money but definitely not time & hassle. Belize City is a crowded dirty city just like all the rest around the world - I like to get out and get to the beach so I would say pay the extra few dollars to fly round trip, and save money on something else. Also you get awesome aerial views of Ambergris Caye -you could even see the house you will rent.
San Pedro airport to your house - lots of taxi type vehicles will take you - but if you work with your rental person your ride will be ready & know where to take you - you can ask the driver or let your rental contact know if you want to stop at the groc store on your way to the house to pick up quick beverages, ice & snack supplies.
If you have a golf cart you can always get supplies when the stores & restuarants are open.
Whether you need a cart you entire stay is up to you.
If you will be scuba, snorkel & fishing everyday or going to ruins on the mainland then you will be spending time & money for those fun activities. One catch is the weekly rates are way more reasonable than day or hour rates - so if you want a golf cart a couple of times - or if you will be doing lots of food & beverage shopping then you might want the cart all week. It is walkable to town but most tourists don't want to walk daily back & forth - it is the tropics ie HOT. I like exploring with the cart one day up & down Ambergris Caye - it makes for a fun day on land. So - if you are staying at the house all the time you won't need a cart. If you want to get out day or night then get a cart. Taxi's cost money also - so sometimes it is cheaper to rent a cart. Check the home page for this site, Marty has many information categories listed on the left list - just click & go! I suggest looking at the maps then you will have an idea of where things are located on the island. Also Travel hints will get you to ferry information - also 2 ferry schedules - one for the island & one ferry to get to the islands from mainland Belize.

Food & beverages can be stocked at your rental & ready to go as mentioned by Marty. Wether Simon does it or your rental contact,
You can arrive in San Pedro and relax at your house with all of your supplies there. Cigarrettes & cigars & special wines might be you most difficult items but beer, food, water & beverages are easy to find in many places.

The Island is west of the reserves. Only beautiful Caribbean Sea lies East from Ambergris Caye - until Jamaica or another island!
Belize it!