Back in marathon days, I tried doing 90-100 but later found less was more. I never recovered on that regime. Always knackered.
I ran much faster times on 5 day running. A very long. A moderately long fast, a set of long reps and maybe two pace runs over 10 and 6, was maybe 60 total.
Translating to fells a 4 -6 hour slow , a 2-3 hour fast. Two one hours and a set of hill circuit reps lasting an hour. All my best times came from those, and could do any AL off that training.