There are many lovely hiking trails at Castle in the Clouds, which is not far from Wolfboro. Mount Roberts and Bald Knob are both wonderful. You don't go in the main entrance for Castle in the Clouds coming from Wolfboro, you go past it and take a right at what I think says its a water bottling plant. It brings you up to the back of Castle in the Clouds to where the current stables are. Farther down that road you will see what used to be the stables but is now an excellent restaurant with a gorgeous view of the lakes (if you want to hike after your hike). You can buy a trail map of the area in the gift shop near the restaurant.

Another nice hike (short one, only a mile) is West Rattlesnake. It looks out over Squam Lake but it is very popular and you will see many people. Across the road from that is the Percival Morgan Loop. It is longer (3 or 4 miles I think) but you again get a gorgeous view of the lake (and less people).