I used a 108 link D.I.D. premium chain (~$100) and a 46 tooth JT Sprocket rear (~$35).
14/46 gearing works well. I run about 500RPM more in top gear for any given road speed (at least in the mid-range
) and have more power for sand and hard starts off road.
Buy a 13 and 15 tooth front and you can run stock ratios to really low offroad gearing.