This off-trail hike follows my Black Cross Butte route to the saddle before making a mean direct approach to Fish Creek Peak.
From the pullout dip through the usually dry creek and head up to the first bench. This ego buster slope starts out steep and just gets steeper. The final push up is a 55 degree huffer. On the bench keep left up to the second bench. Cairns should help lead the way for this next section up to a saddle that's the only real break in the wall looming ahead. If the cairns fail you the key is to aim right or you'll waste time going through vegetation.
From the saddle continue down the ravine on the flip side. Stay high on the right bank, there is one section you'll drop down into the ravine for a short distance, but get back out soon or you'll hit vegetation galore. As you appoach the apparent confluence you want to get further right and cheat the confluence. Fish Creek Peak is the huge rock-butte looming above. It's easiest to access from the slanting ridge on the right. It is doable from the left but it's not as direct and you're more likely to get frusterated. Here's where it just gets nasty, you have to cross this Amazon looking forest that lines the ravine. It's at least twenty to fifty yards of hell no matter how you tackle it so just have at it.
You can head pretty much straight up to the peak but the time spent fanning wide to the right is well worth it. Once you get on the ridge follow up to the rock-butte peak. It's easy climbing that spirals the back side (really west side) up to the top.
If you're familiar with upper Fish Creek then that huge wall spanning the west ravine might look a little familiar. There's some fair distant views too, but... Now for the bad news. This isn't the greatest destination. Other hikes such as nearby Black Cross Butte or Bronco Butte have more "breath taking" views.
Return by the same way but be careful as accidents are prone to happen on the steep loose decents.
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.