bad head gasket or stuck thermostat?

Hello, I have had a problem with my 2001 dodge intrepid overheating after about 15-20 minute drive. my fans seem to be running (However I am not very informed when it comes to cars) both my mechanic and I think its one of two problems. either a cracked head gasket or bad thermostat. the reason I am still unsure as to what is causing the problem is that I am seeing no signs of a cracked head gasket ( oil is still honey gold, No leak from tailpipe, No excessively white exhaust, no excessive loss of coolent, coolent still seems clear).

Is it still probably the head gasket? or is it a stuck thermostat?