Check with rangers or others involved the the areas you intend to hike in. Some of our state parks have volunteer associations tied to them (because the state can't afford to pay all the employees they need) that lead hikes where you could meet a hiking partner. Other groups that lead hikes are native plant societies, bird watching groups, and community colleges sometimes have classes that go in the field to study their subjects (usually, plant, animal or geology related).
"Bicycling is a big part of the future. It has to be. There's something wrong with a society that drives a car to workout in a gym." -- Bill Nye