Well I am so pleased that you have asked for treadmill routines, as well as seeing the response from PrettyKitty1. So glad to have some runners in the house with me! ; )
I also prefer to run outdoors, but I have to watch the surfaces because asphalt tends to really make my legs hurt if I go too far or too hard. In the winter I am forced to move indoors at the rec center due to my asthma (cold air really wreaks havoc with my breathing).
OK...so for my actual treadmill routine. It sounds as if the treadmills at my rec center have settings that are a bit different than the one that you are currently using, but hopefully this will give you an idea of what I am doing.
Before I ever set foot into the rec center I decide the distance that I will cover on this day on the treadmill. I never allow myself to do less than what I have decided unless I feel that I have injured myself and that is the only reason that I ever back down from the distance that I have decided upon.
I begin with a warm-up of walking for 5 minutes at about 3.0 mph and 2% grade. Next I progress to fast walk/jog intervals. I jog for 60-90 seconds at 4.7 mph or faster (keeping at that 2% grade) and then walk for 4 minutes at 3.7 mph. I continue this interval type situation until I have reached the final half mile of my distance that I have set before hand. I like to use that last half mile as my 'leaving it all on the field' stretch giving it all that I have, but ensuring that I don't set out so fast that I can not finish the entire thing. How fast and at what grade at this point will depend upon your personal endurance level at this time. After I have entirely completed the distance that I have set out for myself, I walk at least another 5 minutes at 3.0 mph and 2% grade for a cool-down period. I personally never leave the treadmill without having gone at least 3.2 miles (5K) in a session (distance only counted during the actual workout and not warm-up or cool-down).
Every once in a while if I am feeling up to a challenge I will dramatically increase the incline that I am using for a period of time during the workout portion.....my legs really notice the difference.
My work out routine is running 5-7 miles either on the street or on the beach (Beach is harder, sand makes you work harder, ouch) I usually slow down, but do not stop, and only walk if I have gas or really, really need to drink water. Have you heard of the HIIT? With this program (and running and spinning)I lost 25 lbs real fast. I was so glad!! I still do the HIIT. I just don’t do it every day as it isn’t recommended, or necessary. It’s THAT good!