Running will keep your heartbeat up and definitely make you lose weight, probably more than hiking would simply because running, in terms of energy required, is a lot more vigorous than hiking. However, hiking, ecspecially with weight on your back and on extended outings, can really give you a good quad workout as well as beautiful scenic views and time to really be peaceful. I live really close to the rocky mountains so i've been hiking for about six years now, and my quads are significantly stronger compared to my lifestyle when I lived away from the mountains on the east coast.
So really its up to you. I get bored easily when I jog, but I think that from your point of view you might be better off just finding a way to do both, as although they both are a great activity, they both have advantages over the other. You might just want to weigh WHY you are doing this cardio and figure out which one you need more. If you are trying to lose weight, do more running than hiking, and vice-versa.
Hope that helped.