The trip is 3,464 miles, with a 3,462 mile step 9. The trip time is given as "about 29 days 1 hour". Presuming the 1 hour is for the 2 miles at the beginning and end of the trip, that makes the necessary progress for step 9 about 119.4 miles per day. Leaving 8 hours per day for rest, that's about 7.5 MPH.