Harder than it seems
Engineer Mountain is only 12,968' and so ordinarily you would expect it to be overlooked in Colorado. However, it is very popular as it is prominent over US 550, easy to access, and offers great views. It is harder than it seems like it should be from the data, as the hike and climb is steep, the terrain on the mountain is loose and it feels like it wants to slide, and the ridge is pretty exposed.
The hike begins easy enough. From Coal Bank Pass, go north on US 550 a couple of hundred feet or so and find the dirt road to the west. Hike this, or drive this, to the parking area and sign for the Pass Trail. This trail is a nicely built Forest Service trail through the spruce forest to treeline where it meets a cross trail. You'll gain a fair amount of elevation and most of your miles in this section.
Once you meet the cross trail, you'll be directly below Engineer Mountain. From here, you can see and follow the obvious trail leading to the mountain's base. It begins to go up slope and shouldn't be too hard to follow. As you leave the red rock and enter the white rock, the situation changes. It shouldn't be overly difficult, but you do have to look for the trail at times. You'll encounter a few sections of scrambling before you get to be about half way up. When you get to a chimney section, you can either climb up that, or do what I did: as the trail enters the short deep section of rock before the chimney, climb up to the left and follow the slope to the top of the chimney. From here it is never very hard, but the rock feels dangerous and you're on a high ridge. This is more of an issue when coming down. Descend carefully the way you came.
Engineer is not as easy as you might think, but a lot of people summit it. I would not do this casually in monsoon season, as even though not terribly high for the state, it is a high area and I would not want to be on this rock when wet. Never mind the lightning. Really, given the choice between a late start on a 14er walk up or this during the peak of monsoon season, I would take the walk up.
Check out the Official Route and Triplogs.
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.