USGS-based Trails Illustrated maps are more current than USGS maps and are specifically designed for recreation use showing trails, facilities, trail highlights, parking, etc. Printed on paper-like recycled plastic which I've found to be extremely durable. Projections are 1:111,850/1:62,500. Awesome, excellent map for these "twin" National Parks. This is an amazon.com link, which will save you a few bucks off the retail price.
This is a .jpg on the YosemiteFun.com website. If it shows small and blurry on your browser, just enlarge the photo. (Sometimes the latest versions of Internet Explorer scale a photo to fit your screen.)