When the time comes to find a temporary job to fund your travels, try these possibilities:
National Parks Service
Work for RVers and Campers
Recreation Resource Management
Back Door Jobs
RV Resources lists employment possibilities.
Full Time RVing has a list of other potential employers who look especially for temporary or seasonal employees.
Jena from Learning to Live Outside My Box lists a few different resources, too.
Experts from MoneyGeek offer this overview of outdoor careers.