Thanks for the tip about the sharpie, I will remember that!
Before going to the museum in SF, someone who worked at our hotel told me she loved going there and could spend days and not see everything. That made me a little worried since I only had 1 day for the museum. Right after I got there (FYI they are closed on Tuesdays) I was told they now allow non-flash photography, I was so happy and very glad I had brought my camera along.
I was done touring the museum in just a couple of hours, but I admit I did not read every single thing. I would say for a regular Disney parks fan it is probably not worth it. It is more for fans of Walt himself and the history of the parks. I enjoyed it very much, but one visit is probably enough for me... although, if I were in the area again and had someone who loves Disney (like DD maybe) I would go again.