The below is just one image from my visit in January. I've been back subsequent times since then, but this image gives somewhat of an idea of the terrain that the Confederates contended with on the approach.

I'm just uphill from Rose (Rose's) Run looking at the Triangular Field in the middle foreground. Little Round Top is in the distance. The pinnacle of Big Round Top is on the far right of the photo and the Rose Woods is on the far left, slight obscured by the small tree I'm standing next to. Where the stonewall in the Triangular Field starts to slope down is where the larger area of Devil's Den is. A good eye can make out the big tree present in Devil's Den. A real good eye can make out the cannon's from Smith's Battery. The Slaughter Pen is obfuscated by the landscape, but I note it's general area in the next photo. Also cutting across almost the center of the photo, just above the cattails and marsh reeds is a white patched line of snow. These days it's a hiking trail. In the past it's the railbed of the Gettysburg Electric Trolley.
One can possibly make out the monuments on Little Round Top and Devil's Den, though those are harder to see in the image.

The areas I mentioned above, labeled on the image.
Finally I just made a quick Google Map overview of the area:

The approximate point I was standing at:

Some of the items mentioned above either labeled by me or Google:

As an interesting side conversation, there's a post at Civil War Talk that discusses where the Plum Run and Rose Run meet. Incidentally a subtopic has folks talking about the naming of the Rose Run portion.
https://civilwartalk.com/threads/conflu ... ms.171475/Also, Gettysburg Daily has a segment by Rich Kohr, a Licensed Battlefield Guide on the Electric Trolley:
https://www.gettysburgdaily.com/battlef ... c-trolley/Part 6 covers some of the area of my photo, as well as the controversy of the Big Fill:
https://www.gettysburgdaily.com/license ... ey-part-6/Part 7 Covers the Devil's Den area:
https://www.gettysburgdaily.com/license ... ey-part-7/