Canyons are inherently risky. Flash floods occur without notice on sunny days. Technical skills & surrounding topography knowledge required yet does not eliminate risk.
It's all Up!!
Hershberger Peak is the highest point in the frontal range adjacent to the Marble Canyon drainages, yet all traditional routes to reach that high point are accomplished through connecting on trails running near the mountain, or climbing one of the canyons, or crossing The Mesa and hiking the upper Mesa ridge.
Yet there is a direct route, right up the western ridge system that divides the Northern and Southern Marble Canyon drainages. The nicest route begins by moving up the southern Middle Marble canyon, exiting that drainage nearly immediately on to the ridge on the left (the dividing ridge between the northern and southern Middle Marble Canyons. Following that ridge up to the upper basin of the northern Middle Marble Canyon, then traversing over to the ridge line to the north (the upper portion of the southern Middle Marble Canyon.) From that point it is simply a steady uphill, shifting back and forth on the ridge line to enjoy views to the north of Marble Canyon north drainages, and to the south, the middle and southern Marble Canyon areas. The ridge line hiking shifts from moderate steep grades, to very steep areas, but both can be cross angled, creating effective switchbacks to soften the climb.
Hershberger Peak is reached on it's western side, avoiding all the traditional trails and the other ridge and canyon approaches.
Once on the ridges, it is simply a matter now of moving steadily up, choosing your route based on what canyon views you desire.
To reach the ridges, from the mouth of the main canyon hike a mile into the southern drainage, and just before the "narrows", turn left into the small boulder filled drainage and enjoy the steep but easy bouldering for about 100 yards, glancing to your left for access up and through the deeply eroded cliffs... move out of the drainage to that ridge line on your left, then enjoy the easy trekking up along that mostly open ridge.
An alternative beginning route: instead of following the main southern Canyon, at the split between the North and South canyon drainages, head up towards the left of the small shiprock formation... the drainage on the left of that will carry you up and around and into the northern Middle Canyon. It looks like that is just a small side wash that will end in a few hundred yards, but in fact that drainage continues on for over a mile, forming the very nice northern Middle Canyon cut, ending on the ridgeline where this route traverses to the north.
There is work underway to convert this route into the Hershberger Peak Trail, making it the primary route to access the peak. Once the trail is developed, this route will provide the shortest route to the Peak, though also the steepest!
WARNING! Hiking and outdoor related sports can be dangerous. Be responsible and prepare for the trip. Study the area you are entering and plan accordingly. Dress for the current and unexpected weather changes. Take plenty of water. Never go alone. Make an itinerary with your plan(s), route(s), destination(s) and expected return time. Give your itinerary to trusted family and/or friends.