Madness I know but I’m really struggling to avoid entering my first 100 mile ultra run next September. I’m looking at the hilly Cotswold Way 102 miler with a 30 hour time limit. It runs from Chipping Campden in the Cotswolds to Bath. 53 of the entrants survived it last year, so it can be done, although it will be very demanding physically and mentally, especially because of the sleep deprivation factor over the 30 hours – fall asleep for long and you won’t meet the cut off. Training and nutrition will also need to be spot on. But I’m sure it will be very beautiful running country. More details can be found here:
There is also a YouTube video from a guy who survived it – search ‘Cotswolds Ultra’.