Volunteer to do talks on the subject of conservation and have a collection, or collect admission towards the trip.

Do you bake? Ask permission, and set up a table and sell elephant-shaped cookies, for example - I can give you the recipe I use to make dog-shaped cookies that I bring to Findlay if you'd like ... You can get an elephant-shaped cookie cutter for under a dollar ... and people like elephants!

Peanut brittle candy sale fundraiser? (Elephants liking peanuts brings that to mind ... any nearby candy company that might help?)

Car washes are often good fundraisers if you've got the human power - poster with an elephant spraying a car ...

And do you have a Thai restaurant in your community that might help throw a fundraising dinner? Restaurant will sometimes do "a portion of tonight's sales will go to x charity" events ... or they might have ideas as well.