If you're traveling with children for an extended period, as the parent, you're going to be looking after their ongoing education while you're away. The ASTC Travel Passport Program provides free access to many great science centers and museums across the USA and a few overseas. What a blessing for those homeschooling.
One of the benefits of becoming a member of your local AZA-accredited zoo or aquarium is discounted (typically 50%) or sometimes free admission to AZA-accredited zoos and aquariums that participate in the AZA Reciprocal Admissions Program. There are hundreds of participating facilities across most of the USA.