At the Pony Express Monument marked on the XP Route map just past Mile 1794, there are two possible routes.
The first turns southwest and heads more or less straight to Robert’s Station. The distance is about 10 miles. This is the route followed by the official XP Bikepacking Route and marked on the BLM route of the Pony Express Trail (around Mile 67–https://ridewithgps.com/routes/34091538). This is the route the Simpson Expedition took (Jesse G. Petersen, A Route for the Overland Stage, p. 61).
Jan’s “True as accessible” route at Mile 1676 (https://ridewithgps.com/routes/34516845?privacy_code=ESM1W5E3dAJJhaEI) continues straight at this point (northwest on Highway 278 through Garden Pass Canyon) to go north over Mt. Hope before turning southwest to Robert’s Station. This route is 14 miles, and seems to include more climbs than the southern route. It also may offer access to numerous springs, as yet unscouted. This route is marked on the US Topo map as the Pony Express Route.
If Burton’s mileage estimates are reasonably accurate, the historical route seems to go north around Mt. Hope.
Cross Moonshine [Diamond] Valley. After 7 miles a sulphurous spring and grass [future site of Sulphur Springs Station?]. Twelve miles beyond ascend the divide [Sulphur Springs Ridge, according to Peterson]; no water; fuel and bunch-grass plentiful. Then a long divide. After 9 miles, the station on Roberts’ Creek, at the E. end of Sheawit, or Roberts’ Springs Valley [Kobeh Valley]. 28 Miles
Richard Burton, The City of Saints, p. 512
Lexicon: “Simpson indicated that the natives of the area called the stream She-o-wi-te, which he understood to mean Willow Creek, and that is what he decided to call the stream.” It later came to be known as Roberts Creek, after Bolivar Roberts (Jesse G. Petersen, A Route for the Overland Stage, p. 62).