When I'm on a road with a lot of signals, I usually take a swig at red lights. If not, or if the lights are gloriously all green, I try to be conscious about drinking at least every 10 minutes ... or by feel. I'm thirsty, I drink. But I HAVE gotten dehydrated on days that I "thought" I was drinking enough, so I try not to only go by feel. I've only gotten dehydrated on especially long or difficult climbing rides when it was a hotter than I was used to riding in. The hotter it is, or humid, the more you need to drink. And when you're climbing, there are typically no signals to remind you to take a drink ... and if you're breathing hard, and already going rather slow, it's hard to slow down enough to settle your breathing to get a swig in ... but try you must!!!

Sounds like you had a great ride! Keep it up!