When my kids were little and wanted pressed pennies, we prepared before our trips. We bought some of those mini-M&M tubes. Then we ate the M&Ms (duh. and yum.) and used the tubes to stack 2 quarters - penny - 2 quarters - penny - etc.) in the tubes. Sometimes we collected pre-1982 pennies to use, because those don't have the added zinc. Or we just found very shiny new pennies.
I believe they still have change machines in the laundry facilities at the resorts, although I'm sure those will go away as they get the new systems.
Have fun!