I do same as Proudboy - carry Chrismar, Fisher, and MacKenzie.  I hand scribble notes from PCD and tips on bulletin boards or by email/messages on my Mckenzie, and cross check pictos and camp sites, etc.  May even print a google earth view.

I have grown to like to plan in my house and tend to lay out all of tme McKenzies and Fishers on my floor - usually in dead of winter - and figure out which if any I need to buy, and order them through their websites - and find it most economical.  I feel bad that I'm not supporting the outfitter, but I always have the maps I want.  I don't feel so bad about not supporting REI or Cabellas.