Get a discounted or free national park pass. I once frowned on this but with the ridiculous entrance rates I think it is only fair. Get a geezer pass... over 62 gets a lifetime pass for $10. Get a free lifetime pass if you have any documented disabilities... and I mean any that could impact your enjoyment. There are families getting them for ADHD kids. NPS can't ask what your disability is nor can they ask how disabled are you.