It's a 99 Tacoma. Coolant level is fine, overflow bottle fluid is where it needs to be.

Replaced thermostat with OEM Toyota one and gasket, OEM radiator cap and flushed coolant and bled air.

It seems to start to do it going over 50-60mph all the time, but, every once in awhile it will do it on the street, 30-40mph. If I don't turn on the heater it seems it will just sky rocket

What is left that it could be? Water pump? Head gasket? How do I check those? What else can I do?

Probably a water pump. When's the last time you had that replaced along with your timing belt and the accessory belts?