I just answered this in the other post, but I'll restate it here as well.
Ethically, I only counted the time it took to get there and back. From a legal perspective, I remember reading something about that a while back but I don't know where. Still, if you're tooling around in a C-150/152, a trip to an airport 16 nm and back will still net you around .7 hours, with the startup, taxi, runup, climb etc...
My rule of thumb when it comes to hours is to be conservative. I would hate to have the integrity of my flight hours come into question during an interview. Others may not care. But I sleep well at night.