I would appreciate any and all advice on this. Just some background - I'm a former aerobic instructor of 20 years, have run a full marathon last January 2009 and approx. 7 halfs over the last year and a half. I have a training confliction for the first time!

This year I'm running the Army 10 miler and Marine Corps Full. What is happening is the Army 10 miler is taking the place of my 20 mile training run for the Marine Corps Full on October 25th.

Here is my schedule leading up to the race:

Week OF

13-Sep          5m     5m     5m          19m     

20-Sep          5m     8m     5m          12m     

27-Sep          5m     5m     5m          20m     --THIS IS THE ARMY 10 MILER

4-Oct          5m     4m     5m          12m     

11-Oct          4m     3m     4m          8m     

18-Oct          3m     2m      2m          RACE--MARINE CORPS FULL

Should I switch the 20 miler up to The week of September 20th in replace of the 12? So I have a 19 miler and 20 miler back to back weekends, then taper 4 weeks before, or what? Any suggestions from seasoned runners would be really appreciated.