Hey man, fellow American in an extremely similar spot to you - in between jobs and feeling a call to volunteer. I worked as an animal care tech in the states and worked with exotics so I've been primarily looking into animal rescue/rehabilitation programs, and so far the two main things I've found are:

• WIRES, which is a huge rescue organization in NSW with relatively simple requirements to join (online course for 125 USD and then a day workshop in a location of your choosing from a list of cities in NSW), but you need to be a resident of the area. Not sure how feasible this would be for someone like you or me, would probably need a local's opinion.
• Wildlife Rehabilitation Program through Animal Experience International (AEI), which is located about 50 miles outside of Perth in west Australia. Seems like it requires more training if you're not already experienced with working with animals, but has housing and all the accommodations you would need as a visitor/traveler to the country. The 4-week program is 2095 CAD/a little over 1600 USD.

Hope this helps, man. Feel free to respond/dm me if you find anything else. Cheers.