My fiance and I try to hike a lot when we are up north. It's not the same down here in Miami. We hit up a lot of trails in northern CT and upstate New York. Added bonus is the drives to these spots are usually very fun...some cool stuff to consider when hiking...
Geocaching - almost all hiking trails/parks have numerous geocaches hidden in them. A very fun activity and can be done from an iPhone now - no GPS required.
Always wear pants because the bugs eat us alive (doesn't apply in winter). I usually use the
best tactical pants I can find as they are versatile, comfortable and usually have more pockets than typical sweatpants. They can also get wet without much of an issue.
Try to route out the most fun drive there...especially when heading into the mountains. Sometimes there are some killer side roads that are just a few minutes away from the main in's/out's that the majority of people are using.
Make sure you have a spare tire or a tire repair kit! Twice while going hiking I've gotten a flat miles away from the nearest service station.