Overheating

Okay, so I have a v8 Northstar engine. It has an overheating issue. I can fill full of coolant and by the time I drive it over the bridge or across town she'll say coolant hot idle engine. What could it be? Thermostat? A leak or clogged line? Pressure problem? Water pump? Only has a little over 82,000 miles. Need to get it fixed as I have three children and need to be able to get where we need too without it overheating and leaving us stranding until it has cool enough to drive and we try make it where we are going before it happens again. I am frustrated. The faster I go the faster the car will overheat as well.