Lets not over complicate this issue and tear off heads just yet!

There are two main reasons to replace your head gaskets.
1) Coolant in your oil
2) Combustion gas in your coolant, this will cause overheating and should be tested for prior to any further action!

If you have run your car on a several hour trip without issue, and have had no history of overheating, I would not lead toward a head gasket issue.

Let me first ask you this simple question. What type of coolant cap are you using?