Success just with hiking and trail running?

For years I didn't have a gym membership, and I stayed in great shape. I think you can totally do it! I hiked a lot, and lifted weights at home. I highly recommend getting a barbell and plate weights for home... I found mine at a used sporting goods store for cheap. Also, you can google how to do strength training using only body weight, for something free to do at home. I used DVD's (Cathe is my favorite). I have a gym membership now, but I still hike and work out at home as well. Good luck!

Who said lifting weights is the only way to get fit and live healthy? Actually your settings are even more favorable than most of us who live in "cities" and supposedly have "gyms".
Gyms are overrated. I used to have the same issue as you before. I only had the Forrest and the sea at summer.
For starters: I would do early morning running (much MUCH better than treadmill)
I would use the stairs at my building for some quick effective cardio explosions.
I would use my bike for some off road adventure.
I would find some tre branches straight and high enough to do some pull ups and general calisthenics.
At summer swimming and water was my best pal.
And so many many other ways to train. It is actually much more enjoyable than a dry gym life. I go in gyms now because I live in the city and have no way of getting my regular dose of nature, but I assure you that from a training perspective I MISS the rural country I was!

I sent you a friend request just now because we're in very similar situations-- I live in rural VT too and have the exact same exercise options and preferences! From your description of what the area you live in is like, with ski center trails, I have to wonder if we live in the same town.

I've been decently successful so far this winter with getting in much better shape, and am still working on losing weight (started that project in January). In summer here, I have no trouble getting strong, as I have a large vegetable garden that's a huge amount of work, and enjoy hiking and trail running. In winter it's a different story. I like XC skiing, but not every day-- winter can be hard for me to take (isn't this storm we're getting absurd?!). And because I'm trying to go from 116 lbs to ~105 (I'm quite short), I decided I needed to weight train. So I got some pairs of dumbbells (2, 6, 8, 12, 14 lb per dumbbell acquired over a stretch of about a year), cheaply on eBay, and use those. I'd kind of like to get into lifting heavier stuff eventually, but I don't think we have room for a weights rack and I'm concerned I might hurt myself without guidance in how to use very heavy weights. I have found lots of circuit training weight/cardio workouts online-- About.com has some good ones. I also have a resistance band ($10 or so) and an exercise ball. We have squeezed the workout stuff into a space in my partner's home office in our tiny house!

I think it is completely possible to get in great shape without a gym! . . . Have you checked out whether there are any Zumba classes in your area? They are super fun, cheap ($6 a class where I am), and great exercise for winter.

If you want to add in strength training I highly suggest body weight exercises. I have become way stronger and more defined doing that. You can use tables and chairs and doorknobs in your house to help. Check out Mark Lauren's bodyweight training.

Also, I have found that regularly doing yoga has helped my strength and balance a lot. Check out this website for good, free yoga videos: doyogawithme.com.

I don't go to a gym either and I've managed to lose over 40 pounds. My strength, stamina and endurance has significantly increased from hiking regularly.

Have fun!