Don’t put too much weight on being ‘near’ the mountains or DC from Charlottesville. 1) it’s more like 2+ hours to DC from Cville, and the Blue Ridge mountains are about 2.5 hours from either Cville or CH. And, CH has beaches w/in 2 hours instead of DC. More importantly 2) students at both UVa and UNC tend to make that kind of road trip very rarely unless they have a particular interest.
But really, OP, as you can see by the above comments, you have two great choices, which are more similar than different in the things that can be measured objectively (unless you are looking at Engineering, but you would already know that).
You mentioned diversity, which is a good example. You can look up the stats, but as I am sure you know how a place feels is more than just #s. Really, just go and see. Revisit weekends are coming up. Visit both- it will be worth it.