apart from what Jon said above, there are numerous variations on how to get re-supplies, depending on what mode of transport you use to get there (public or private), and also whether your route is circular or linear.
in the past i have forwarded supplies 'poste restante', whereby you pick up your supplies at a post office, freeing you of the need to carry too heavy a pack. for that to work you NEED a predetermined route.
i have also driven in close proximity of a chosen route and stashed and/or buried supplies that i pick up during the walk.
come to think of it, i've used loads of different methods to gain supplies, all with the same thing in mind:- travelling light(er).
tell me a bit more about your transport/route itinerary and i'll try to give you some more ideas.