you wont find anything near the quality of 7.5 minute maps....that I know of
I have done extensive cross country travel all over the sierra, I get by just fine on tom harrison maps. Now with the internet I can study the USGS maps at home. before the internet, you just went for it.
I sometimes create my own maps using USGS maps for short hikes. you can view them, take a screenshot, then cut and past it together in paintshop.
I just did one for a loop I am doing this weekend because I am taking someone along, and wanted him to have a detailed map. I prefer solo for off trail hikes, so if you are going in a group please make sure everyone treads lightly! :)
Nat Geo has some very detailed maps of yosemite....NW,NE,SW,SE yosemite. I do have the set and they are very nice. Scale is 1 : 40,000 with 50ft contours.
How much experience do you have in cross country travel?