How can I get in shape for hiking mountain trails?

Recently I went on a hike organized by a group I am a member of. We went to Franconia Notch national park in New Hampshire. Our planned route started from Trailhead, at an elevation of 1,950 feet (594 m) and followed the Waterfalls Trail up to Little Haystack Mountain at 4,760’ (1,451 m) and then ran along an alpine zone ridge to the peak of Mount Lafayette at 5,260’ (1603 m)—for a net rise of 3,310’ (1009 m)—before looping back down Mt. Lafayette to Trailhead. The total trail was 6.2 miles (almost 10 kilometers). Some parts of the trail were pretty steep.

It was fantastically beautiful country to hike in, and I enjoyed the early part of the trek immensely. However, my legs grew more and more like rubber the higher we climbed.

I made it to about 500 feet below the peak of Little Haystack when the legs basically said to me, “We’ll give you two choices. We’ll take you to the top of Little Haystack, but if you make us do that that’s all we’ve got. We’re not carrying you back down. Or, if you’d prefer, turn back now and we’ll get you back down to Trailhead.”

It was embarrassing to have to let the group go on without me, but I really had no choice. I had used up everything my leg muscles could give me.

I got a pair of walking sticks. My arms can do a lot to assist. But living in suburban Boston with no nearby mountain trails, and having no car to drive to ones in Western Massachusetts or New Hampshire, what sort of exercise routine do I need to add to my workouts to ensure that I can take the next hike in stride? Currently, I work out daily alternating between odd-numbered days doing heavyhands swinging 15 lb. (6.8 KG) weights and 125 reps. The full set of different swings takes about 30 minutes. On even numbered days I do a full set of different dead-weight lifts. Currently, I do 15 reps each of curls, presses, flies, floor flies, back-rows, deep knee bends, double-leg calf raises, and leg lifts while laying on a matt with 5 pound ankle weights strapped on. This also takes about 30 minutes.

How do I modify that routine to prepare for mountain hiking?