There are delivery type ebikes, that could carry 2 or 3 sets of spare batteries, and your gear. You would just need additional chargers to charge overnight.

Rural China is often hilly or mountainous, so keep that in mind. But you can find an outlet or a minivan to the next town without too much issue.

Wow cross country on a dian dong che? Nice recipe for getting stranded in the middle of nowhere. Weight increase from extra set of batteries will also increase energy consumption.