That is an interesting question. You should run the course again with a 2:1 ratio, and let us know what the result is.


Looking forward to seeing you post the results.

Good Luck

Let's do the math on this.
Assume that you can walk at 15 min miles.
If you walked the whole way, your time would be about 3:20, as opposed to 2:37 for 12 min averages.
If you can average 12 min miles with a 7:1 split, then you must be running 11:40 min miles.
If you ran the whole way at this pace your time would be about 2:18, which is about 20 mins faster than your 12 min walk/run time.
I suspect that at this stage, a 7:1 split is too long, and you should try something easier, e.g. a 4:1.
Running for a shorter time, you will be able to improve your running pace dramatically, probably down to 11 min miles.
Problem solved? Partly, since this brings you back to 2:30, 10 mins faster than your race time.
Two suggestions.
1. Try the different split and see just how much faster you can run, and don't be afraid to give it a real go - you might be surprised - run the first 2 mins hard, then say to yourself - only 2 more minutes and I can take a break!
2. Make a positive effort to improve your walking pace, which you can do on your running rest days. Just imagine if you get used to walking comfortably at 12 min miles, which is perfectly achievable.

With more training, you'll be running 10 min miles, walking 12 min miles and running sub 2:15.
Good luck.