I would not do it this close. I just did the Hanson marathon plan to train for Dopey. Their plans are a fair number of miles, and the beginning of the plan, I think, is key in that while you build the mileage, the runs are easy pace. To jump in now, I think you risk overuse injury.
If you're bored (I get it, my switch to Hanson's this time was a "shake it up" kinda thing), why not add in an extra targeted run. You could do some speed intervals or a little tempo work. But I would keep the number/distance short.
I'm sure
@DopeyBadger would have good advice.