2000 Silverado 1500 Z71 5.3 liter get hot when idling?

I have a 2000 silverado 1500 z71 with the 5.3liter engine and just recently i noticed it get hotter when idling or around town. It normally runs at 210 but yesturday I was sitting in my driveway with the truck running and the a/c on for aout 20min, I noticed that the temp shot up the the 3/4 mark in that 20min. Then today i was driving around town and the temp was reading fine, but i stoped to get lunch and turned off the truck for about 10 min and when i got back in and started it the temp was at the 3/4 mark again but then went back down to 210, I then got to work and was moving a couple of light trailers around and it was reading right aove 210 when it normally reads right under 210. The colant is full, no dirt or anything in it, replaced the air filter 100mi ago. So could it be the thermostat, fan clutch? or what? also when the truck is off and warm the fan has no play i tried to spin it and it spun when i moved it, no grinding or anything, but it dosent spin freely, which i think is normal? Anybody have any ideas. I really need to fix this cause in a week i have to drive 500mi to texas and back, Ohh also the truck has 122,800 mi on it.