One of the largest platforms to find volunteer work on a farm is WWOOF (World Wide Opportunities on Organic Farms). There are WWOOF hosts all across the world. Choose your country and register to find opportunities.
A time-tested way to fund your travel is to teach English overseas. If you are fluent in English, get a TEFL certification to make it easier to land jobs.
If you work for a multinational corporation with branches in other cities, ask your company for a transfer or find opportunities for work-related travel. Usually, employers will cover the cost of flights and hotels for an official visit.
If you have experience working with children and want to live in one place for at least a few months, consider working as an Au Pair or a live-in Nanny.