70-200mm - Which one?

[Cage]

I played around yesterday with the 55-300 kit lens in very bright sunlight. Photo's came out looking okay from 200mm to full length, but zooming in on the computer screen they just weren't very finely detailed. IS that referring to a lens being 'soft'?

Unfortunately, yes.

Kit lens, generally, will produce great 'Happy Snaps', however most will reveal deficiencies if you start pixel peeping, ie looking at their output at 100%.

A 70-200mm f2.8 sounds ideal for you, and as you also mention landscapes may I suggest the Samyang 14mm f2.8. Well though of lens at a very reasonable price, and it's chipped for your Nikon.