how long is
depends on how fast you recover and if you get injuries but thinking about it a lot of people who did IM and some who did double IM last july and august did the JW Ultra in the september which was 30 miles.
It will also depend on how hard you are going to race the marathon.........you should retain a lot of your fitness even if you rest for a couple of weeks and then start running again
hopefully 5 weeks is plenty of time between IM's.........
It had better be!
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