For everyone who say feet and pounds get the medieval feel better, I have to say...
Why do you use platinum/gold/silver/copper, then? You should use pounds, pence, and shillings for coins (1 pound=20 shillings=240 pence), and guineaus, crowns, sovereigns, halfpennies, and farthings, etc. And financial money (the one used for accounting, loans, debts, etc.) was different and disconnected from the coinage.
Then, to be even more medieval, if you move a two week walk away from a place, you arrive in a land where people speak a different language, or at least a different dialect of the same language. Common? What's this?