It is, as we all know, a massively tall order. Ice, wind, rain and darkness all add to the challenge. Add it the random factor of drunk moped riders and it's clear that even if Steve manages to avoid mishaps/stumbles related to any of them, he's still got to keep physically fit enough to be able to knock out at least 215/220 miles per day when the weather does take a turn for the better. Realistically, pretty well any day he hits or passes a Godwin between now and the end of February is going to be a massive bonus.