As was mentioned - the Cardinal offers a chance to do the corridor in a Viewliner. Then somewhere between Manassas, VA and Culpeper - the scenery begins to get very nice. Mostly nice fields and farmland - and some very nice horse farms. Then as you get closer to Culpeper (at around 12 noon), it really gets nice... I know between Culpeper and Orange VA it is mostly cattle grazing - rolling high hills, and far off views of the Blue Ridge Mountains (nice). My favorite stretch on the Cardinal is from Culpeper, VA to White Sulfur, WV (which is about 12:30 PM - 5 PM) - simply due to the ruggedness of the mountains, and the challenge those large mountains presented to the original C & O Railway.
Along the old C & O you will pass Charlottesville at 2 PM (historic UVA), climb the Blue Ridge to Afton, VA (nice), enter Blue Ridge tunnel (long) then exit on the west side of the tall mountains in the Sheanandoa Valley of VA - cross the NS Valley line in Waynesboro (no stop). When you leave Staunton VA - heading west - the terrain is much more like Montana for the next hour - with cattle grazing on large open tracks of pasture land on rolling hills - and a backdrop of tall mountains to the west (and East too). I love this part. Not much civilization, and what there is - is old and quaint. It's really like stepping back in time.
Clifton Forge was once a huge rail center - still a major division point. You enter Clifton on the "Mountain" subdivision - which comes in from Staunton, and the "River" sub comes in from Richmond - that is also a very beautiful rail line along the James River of VA - but no passenger service. Mostly coal trains to Newport News VA.
In the 1950s and 1960s the C & O really marketed their name passenger trains well (The George Washington, etc..) using color photos from the Charlottesville area. So from Charlottesville on - the scenery is just spectacular. Mountain rivers, high bridges, beautiful horse farms, orchards and tall mountains. Keep in mind - that the surrounding area around Charlottesville - is home to some of the wealthiest people in the world, so the homes are large, cattle/horse tracks, with gorgeous estates, that can be seen from the train. The views from the train as you climb up to Blue Ridge Tunnel are more like views from an airplane. You eventually look down about a 1,000 feet or so to the valley below. It's not often that you travel by rail - and look "down" so far. Generally rail lines follow the lower river basins and valleys. About 20 years ago I was riding through this section on Amtrak - and a family was in the lounge car or dome car (don't recall the car type) and they were returning from a trip across America and back. They all felt that this section - from Blue Ridge Tunnel to Charlottesville was the most spectacular scenery that they had viewed on the entire trip across the US. But like me - I think they were from Virginia or the DC area - so we Virginians may be more partial to this type of scenic setting. But the fact that they expressed that had an impact on me. I recall that well. So naturally I'm a big fan of the Cardinal. Also - my first few train rides as a young lad in the 1960s was through here on the C & O. Their trains were top notch (domes, diners, Pullmans, etc..).
From Clifton Forge west you pass along the Jackson River (or is it the Cowpasture River?) along a very narrow rocky ledge between Clifton and Covington). Covington is another Rail town with a neat restored station (no stop) on the left - by the yard. Leaving Covington you will hit several short tunnels. This stretch is a favorite area for rail fans. Very tall mountains and steep grades... You will pass "Moss Run" (spectacular spot to watch trains), then the remote Jerry's Run (the highest fill on the C & O Railway), enter Allegheny Tunnel (the "Eastern Divide") and exit the tunnel westbound at "Allegheny, VA - which is also one of my favorite spots. Just gorgeous there. Then on to White Sulfur, WV and home of the C & O Greenbriar Hotel (now a Marriott property). After White Sulfur you follow the Greenbriar River to Hinton, WV an old C & O Rail town and large division point. That is where the New River begins. From here on the scenery is a remote - hard to reach, wilderness area. It's one of the deepest gorges in the entire Eastern US. They say at certain times of the year there is only one hour of "direct sunlight" in the gorge. The New River is all white water - and you will pass rafting excursions. There is no room for a highway - just a rugged river and a thin rail bed and steep sides. So rail is the best way to travel through the Gorge - either Rail or on a Raft. You pass under the outrageously high suspension bridge - funded by US tax payers for the WV Senior Senator (Byrd) who was also a pro rail advocate of the Amtrak Cardinal.
Once you pass Charleston it is still quite nice, but not as spectacular.
I've never been on the LSL but hope to do that trip one day - especially along the Hudson (nice). The Cardinal does offer you a half day of additional rail travel through some very nice scenery. I once saw a link on this forum to a well written New York Times travel story regarding a cross country Rail trip on Amtrak. The NYT writer chose the Cardinal over LSL in favor of scenery (I think). He mentioned seeing America from a different vantage point - not on a highway., and travelled on Amtrak's Cardinal to the Empire Builder. Nice story.