Depends on the game I suppose.
For example, Real racing 2, the save game data is in /data/data/com.ea.game.realracing2/files/SaveGameData.ini - which to access that would require root on both devices..... So you had may aswell install titanium backup on each device and backup / restore.
The game data itself is often in /sdcard/Adnroid/data/com.xxxx.xxxxx but whether any games save their saved data there I cannot say. I doubt it though.