No Gary, the road is off limits to walkers, joggers, runners and everything else except motor vehicles and bikes by special permit.
The Pikes Peak Marathon starts in Manitou Springs 6300', up a paved road for about a mile and then on the Barr Trail which is your typical dirt rocky trail. It is far from being a gentle slope but is every bit as challenging, a rocky gnarly trail as you describe Whitney, only longer and with more elevation gain to the summit vs Whitney from the Portal.
Instead of speculating, come on out next summer en route to Whitney and get some altitude training in here !!
