Toyota Repair: cooling system, radiator shop, anchorage ak

Question
I have a 93 xtra cab dlx V6 Toy p/up.  My son has taken it over and it has been running warmer than usual.  Not overheating but the needle on the idiot gauge climbs higher than normal.  It has about 125K on it and everything else seems is fine.
Through questioning, I don't think he has had the cooling system serviced in, at least 3 years, we live in Anchorage, AK.  My guess is that it is simply time for a flush and new coolant?  It makes plenty of heat.

Answer
I suggest that you have the radiator checked, it may be partially clogged up,flushing it and adding new coolant probably won't help, take the radiator out and have a radiator shop check it and I think you will find the problem there, if the radiator is not the problem I suspect there may be a headgasket problem, the choice is yours what to have checked first, before doing anything, try replacing the thermostat.