There's really no substitute for putting in the long miles running on the
road. There are a couple things you can try to make this a better
- Divide your long runs into several 30-40 minute loops, with each one
ending at your house, or some other place where you can get water, food,
or whatever. The pauses in between loops shouldn't be any longer than
1-2 minutes, then it's back on the road. I do this quite often now--I'm
tired of getting totally dehydrated, especially when I never let this
happen during a race.
- Divide your long run in half, and put in a moderately long ride in
between. This will enable you to experience the feeling of running at a
later point in time without actually banging up your legs for too long.
For example, you could run 1:20, then bike 1:30-2:30, then finish with a
run of anywhere from :40-1:20. The last portion of the combined 2+ hour
run will take place after 3-4 hours of aerobic activity, and will provide
a more realistic "Ironman-like" training experience.
Hope this is what you were looking for-