What seasonal work can fund travel?

Australia has fruit picking, which is commonly done by seasonal labour (a.k.a packpackers). The hours are long and the work hard, but our wages are high and most of the work is in Queensland, giving you access to some of the world's best rainforests and reefs, as well as the rest of Australia or NZ when you're ready to move on. You will need a working holiday visa to get any type of work in Australia.

WWOOF (working on an organic farm). There some opportunities that are closer to "destinations" than others. One the piqued my interest was a community/organic farm near a Buddhist temple in Brazil. There was also an opportunity in Sao Carlos thats in the city, if rural areas are not for you

Just rehashing an answer to a similar question by Ginamin

A common one for European students is Camp America and its ilk. They pay your airfare out to the camp, pay you a little bit while you're there (more if you've a handy skill like lifeguarding, first aid, teaching etc), and then after your time on camp you've the rest of the summer to enjoy the country.

Teaching English as a Foreign Language (EFL) is another one which may offer flights and fairly decent pay, but you'll often need a qualification or at least some experience.

Tourist DESTINATIONS are among the ones that most need summer employees in places like Alaska.

While taking a summer cruise, I was struck repeatedly by the fact that tourist towns typically reported populations of say, 1500 in the summer, and 500 in the winter.

Local populations simply don't provide enough manpower to handle the tourist trade. That's particularly true because some fraction of the locals are vacationing AWAY during the summer. What the locals do is to provide ownership (and some of the managerial talent) for tourist establishments. The rest of the work force is "imported," and typically "comes up" a few days or weeks before the crowds. May (or early June) is a good time to search for jobs there.

Many of the hotels and other other accommodations are only open and staffed in the summer. Closing September 1st (October 1st or November 1st) was a sign I saw a lot.

Basically, there are two types of tourists in these towns; the ones that are there "only" for fun, and the ones that need to "work" their way through to finance their fun. Apparently, you want to find your place in the latter category.

If you're a highly educated type who would still like to see the world and do some travel, you might want to have a look at "adventure travel" companies. These groups commonly have lecturers in the topic area come along to give what people are seeing background and context. I've been on trips with marine biologists, geologists, etc. so that might be something if you're got an advanced degree.

I don't have the name of any particular company because, quite frankly, they fold pretty frequently.