My dd is 7 and she did the pressed pennies... I suggest you bring a roll of "shiny" pennies - and have lots of quarters, in advance, that way its one less thing they have to "whine" about!! She felt very much in control, when she looked at the stores and wanted souveniers, she had her money ($50) to spend, or she could get a "pressed penny" - it worked like magic!! and I did buy the book, and kept it at the hotel and at night she'd like to remind me what we did at the park, and how that penny will remind her of it!!
Sometimes she'd want all 3 choices, sometimes just one - I didnt give her a choice on the quarters ($!.25 I think) if she wanted a pressed quarter, she'd have to use her money!!
Also, dont be surprised sometimes the lines for the characters were short - we went in August...
and if you do a character breakfast (like Chef Mickey's in the Contemporary hotel) you'll want autographs!