I have not done what you propose to do, but it makes me curious whether you are modeling your trip on something you know others have done, or is this a pure shot in the dark, and adventure you dreamed up and got excited about? As I say, it is mere curiosity that makes me ask.

I have so little specific information for you that the best advice I can give is, alas, all too obvious: the more completely you know the language, the more successful your trip will be in every respect. Assuming locals will know english becomes less and less reliable the further one gets from cities and from localities on the beaten tourist path. Knowing the language will not only allow you to gather reliable local information, but also interact with the local people at a much deeper and more satisfying level.

Good luck.