In my opinion...I definately feel that the walking does something...you are almost walking 5 miles a day. Depending on your current goals, this is good or bad. If you are looking to bulk, I would cut out the walking for a bit...otherwise I think it is a good thing, and it sounds like you enjoy it. The only thing I would add is that you might want to not walk on leg days.
Again, all this is just my opinion.
-J