Import/export settings

in the page:
http://musescore.org/en/handbook/revert-factory-settings
You'll find references to MuseScore.ini, the file that contains the preferences. You can copy and paste it in the folder (PC) of destination

In case anyone else has trouble copying over keyboard shortcuts, I'll outline what I did to transfer shortcuts (from Windows 10 to Mac OS Yosemite). I found the file paths in https://musescore.org/en/handbook/revert-factory-settings, then I copied the PC file to my fresh Mac installation of MuseScore. I did NOT restore factory settings.
1) On the old computer that has your MuseScore shortcuts, find the Shortcuts.XML file:
• On a PC, it's in C:\Users\USERNAME\AppData\Local\MuseScore\MuseScore2\
• On an older PC, it's in C:\Documents and Settings\USERNAME\Local Settings\Application Data\MuseScore\MuseScore2\
• On a Mac, it's in Macintosh HD/Users/USERNAME/Library/Application Support/MuseScore/MuseScore2/
2) Make a copy of the Shortcuts.XML file and send it to your new computer.
3) On the new computer, check if you already have a Shortcuts.XML file in the location from step 1. (If you do, you can rename it, move it elsewhere, or simply replace it with the new copy. I had just installed the program and hadn't made any preference changes, so I didn't have the file.)
4) If you are running MuseScore, save any changes and quit.
5) Copy your old computer's Shortcuts.XML file into the place it belongs on the new computer.
6) Open MuseScore and check whether your shortcuts work. (Mine did--hooray!)
I hope this helps someone! :)