The nature will work for you, if you work for it.
It is the best place to exercise. You will have fresh air for your hard working lungs. You will have the beautiful surroundings with natural challenging obstacles you can use for your training. And the different kinds of obstacles gives you an unique possibility to train your motor function in different ways.
Up hill is one of the best thing you can do for your cardiovascular training. And it is so motivating to stand on top of the hill, when you have pushed yourself to the limit all the way up.
Just get out there you will not regret it.
Love, sweat and wisdom