If you enjoy walking perhaps you can look into hiking, just to change things up. Walking is great exercise, keep it up. The human body however is amazing because it reacts to being challenged. When you do the same thing for a long time your body adapts to do it in the most efficient way possible, meaning that it tries to expend the least energy and burn the least amount of calories doing it. That's why you see people upping the ante. At first 1mile is difficult to do but then it gets too easy and you have to add to it. Challenging yourself may mean walkin more hills and stairs, walking faster, adding a weighted best, or walking further. You're already walking 2hrs so you'll have to find a way to challenge yourself without adding more time. Me, I'd rather cardio for 30 min and be done with it than waste 2 hrs of my day so I push hard.
Body weight exercises are wonderful and can really build up muscle.
Fat isn't a feeling
"Food is not the enemy. Hunger is a sign of life and vitality." - Caroline Haagen from The F- it Diet