I was in peak marathon shape 3 1/2 months ago... Haven't done over 11 miles since but am doing a marathon completely on the fly in 2 weeks with a friend, anyone done this before with only like 11-15 miles as a long run? I've been just focusing on speed lately/ high intensity and about 3-5 miles a day, was gonna just do some slow pace an walk all the aid stations, will I be okay if I do that?