We're the type of travelers who intentionally seek out underrated places/hidden gems and lesser-visited spots, even in tourist hotspots. That's exactly why we loved Timber Creek CG. It's on the (much) quieter west end, near Grand Lake and a good distance from all of RMNP's most popular sites. In our opinion, that makes for a much nicer, more tranquil camping experience - and evidently the elk agree, because this campground is a hub of elk activity! The video I attached is from the campground just after sunrise, and we saw and heard tons of other elk as well. If you drive this end of Trail Ridge Road at dusk or dawn, you'll see loads of them too (stop and walk around and bit at some of the viewpoints/pullouts). They're supposed to be great for moose, too, but we personally didn't see any.
We stayed one night each in sites 50 and 17, and both were great. Facilities are basic but clean and sufficient, and fairly close to every site. This is a very popular national park, so while you won't have any real privacy, we did feel like the sites were positioned thoughtfully, so that everyone sort of faces a slightly different way. Highly recommend!