running is running

You can get good results running intervals on the treadmill, so I don't see why tempo runs would be any different. Good point about training in the conditions you want to race in, though.

I run tempo runs on the treadmill in the winter. Here is what I do. I start out with a mile at 6.6 mph (9 minute mile). Then I push it up to 7.0 (8.5 minute mile). Every quarter mile thereafter, I push it up another notch (7.1, 7.2, 7.3, etc.) until I finish a total of 5 miles. After that, I run a one mile cool down at 6.6 mph. Of course, you should adjust the pace to suit your abilities. Another variation is after .15 of each .25 mile, raise the incline to 2.0 for .10 mile. It makes raising the speed up a notch feel easier. Of course, you will burn more calories while maintaining the same leg speed. Hang a towel on the arm rail for you will sweat big time.

Love the long-term goals, yo-sal. Personally, I'm targeting the 141st running of the Buffalo 5-mile Turkey Trot (I'll be 80 in the year 2037 when it occurs)