Wow, I can only do a "liquid only" 1 hour ride if I've had a reasonable meal beforehand. For a 2 hour rides, the only way this would be possible is if I've had a large-ish meal within the last few hours.

Then again, I am a grazer by nature and I always eat little meals and snacks throughout the day. I think, because of this, that I tend to run out of steam a little earlier than most.