I would point out that this forum is dedicated to backpacking in the form of wilderness trekking and primitive camping, far from roads, towns, grocery stores and all other structures of civilization. While there may be a few members here who have also done inexpensive international travel of the sort you propose, the expertise of the participants here is generally focused on topics rather far from those which might interest you. You would probably receive more assistance on a forum more interested in the type of backpacking you are planning.

Incidentally, you are far from alone in making the mistake you did; newbies attempting cheap international travel come here to ask questions rather often. Occasionally we are able to answer their questions, but usually not.

It sounds like you are planning an interesting adventure. Good luck.