Don't forget to check/change the radiator cap as well. A bad cap at higher altitude will send temps up. Is there a coolant recovery tank? And like Jim said, if all else checks out, 210 running down the freeway is not terrible, 220 is pushing it a bit though. We just had a 105 plus day here in Sacto last week and sitting at a drive through in my 03 honda, the A/C started feeling warm, looked at the gage and it was at 3/4(below 1/2 is normal)popped the hood and no pressure in the upper hose. New cap, problem solved.