There are essential things that you will need to find out in the beginning. First is the means of travel available to you at destination. How will you move from one place to another? What are the places that you will be visiting and what is the best means of travel available to those places?
How safe is the transportation system? How expensive it? Then you have to think of where you will sleep. Are there any cheap hostels or camping grounds? Think of any YMCAs, YWCAs, youth hostels or even families that offer their homes for a fee. How is the local food, are you familiar with it?
Being unable to use the big hotel chains, it is important to think about food because smaller accommodation places may not serve an international menu. If you are traveling from a developed country to a tropical developing country make sure to take cholera, typhoid and Hepatitis A&B vaccination and to take anti-malarial drugs two weeks before the day of travel.
After carefully planning and choosing your destination it is time to think of some basics items to take with you to make your backpacking adventure a happy one. First you will need a large, durable and waterproof backpack to carry all your essentials. If traveling to a developing country where safe to drink water may not always be available, think of investing in a mini water purification system.
A money belt is a good idea to buy to carry you cash, passport and any valuables. Get a good easy to set-up tent, easy to carry tent but you may not need one depending on where you are going you can always hire one at destination but inform yourself first. Most tropical destination a have a mosquito problem invest tin one even if you have taken anti-malaria medication those bites can leave nasty marks. Also buy some mosquito repellent cream to use on your arms, face and any exposed areas. You will need waterproof cases one for your camera, one for your phone, a rain coat for you and gloves if need be.
Foot wear is important but you cannot afford to carry too much. If you will be doing any hiking get a good pair of hiking boots, open toe sandals are good for resting your feet and for the hottest destinations. Pack weather appropriate clothing, light fabrics for the tropics but do not forget that it can get chilly in the nights too so have at least one sweater or light jacket. For calling home check to find out the best way to keep in touch, should you add roaming charges to your cell phone plan or can you make cheaper call using calling cards.
Another alternative is to use Voip. Have you and your family subscribe to services like Yahoo messenger or skype and you can make free calls home. But keep in mind that you may not always find internet service or reliable one to make clear calls. You can always keep in touch by email