Hi I would suggest that you bring both debit and credit cards - if you're not keen on bringing them have you thought about getting a currency card, which works in the same way? You just load a certain amount of money onto it and use it like any other card. I would also bring several hundred in sterling and in US dollars to change along the way. Your TM will help you change money as you go and you can ask them for advice on how much to change in each destination. Beware of using some ATMs which may charge you high transaction fees - ask your TM/local guide for advice if you're unsure.
Packing is a tricky one on such a long trip - I suggest you bring clothes that you can wash yourself (bring travel wash) and will dry quickly. On some long tours, I do a mini wash on the first night of a two (or longer) night stay in a particular hotel. Alternatively if you have a lot to wash, many hotels do a 12 or 24 hour laundry service, but check with reception that they will definitely be returned to you within your timescale!
Have a fantastic time!
Bob
