Rob's tracker shows the van getting stuck around Goff at 8:20am Pacific. The data shows the RV moving slow but steady up until 8:20am, at which point there's a bunch of closely repeated points, which are visible on the tracker map as a little circle of movement where they're stuck for about 45 minutes. Then he turns up in time to get a fancy picture at the pool at 12:50pm Pacific.
According to google maps, that is a 38+ mile trek ( link: https://www.google.com/maps/dir/34.9389637,-114.8547084/35.1684307,-firstname.lastname@example.org,-114.8010222,11.75z/data=
The tracker shows them getting stuck around 8:20am, and this photo corroborates their story about it taking ~30 minutes for the truck to get there to help - note the image filenames have the timestamps - and the timestamp for the RV stuck image corresponds well with the track data export:
Specific Blog photo of RV stuck in sand: http://www.marathonmanuk.co.uk/wp-content/uploads/2016/05/2016-05-18-08.50.15-1024x768.jpg
And then Rob's at the hotel 4 hours later in this blog photo at hotel: http://www.marathonmanuk.co.uk/wp-content/uploads/2016/05/2016-05-18-12.52.50-1024x768.jpg
Check out the shadows in that pool image, the shadow sizes corresponds very well to the timestamp of 12:52pm.
Full blog story about the day at the end of:http://www.marathonmanuk.co.uk/2016/05/21/day-3-5-a-pick-up-for-a-hiccup/
So according to them, Rob covered 38 miles in 4.5 hours solo and unsupported in 80F heat (high that day in Laughlin was 93F) to cap off a 70 mile day. And that's if he left the RV immediately after it got stuck and then found their hotel and immediately ran and jumped in the pool. But the story on their blog claims he tried to help get the RV out of the sand for a little bit before packing up to leave solo, and that when he got to the hotel they all went to the casino to play roulette before hitting the pool.... so there has to be *at least* 10 or 15 minutes of that gap taken up by non-running activities. Even if he had ran straight away to the pool, there is no way Rob made that trip on foot. That would be 38 miles at 3:10 marathon pace or likely even better according to their story, on the end of day 4 of a transcon when his best verifiable marathon time is a 3:06.