To beat Tommy's 100,000 informal record he needs to average at least 200 mpd. Assuming an attempt starting on 1st Jan 2015, Steve currently needs to average at least 223 mpd from now until 14th May (day 500). Alternatively, if you work backwards and assume he finishes both the OYTT and the 100k on the 30th July 2016, he would need to average at least 217 mpd from now on. This may seem like a higher total than expected for the apparently "easier" 100k challenge, but is because his average over the previous 135 days (500-365), which spans the moped incident period, is about 154 mpd.
There is a bit of uncertainty in the above because we don't know when in August he is attempting the restart, nor what his average will be between now and the restart. But whatever he chooses, this remains a significant challenge.