It's definitely a dilemma choosing what lenses to use for landscape photography, zooms, primes, focal lengths, how many to carry.
The temptation is often to want to cover every single focal length so the obvious option would be a 24-70 zoom and a 70-200 or 300 zoom. You're then missing the ultra wide though so you might want something like the Tamron 15-30 f2.8... and then you think I'm missing a prime, so you buy a "nifty 50". perhaps a 50mm 1.8... the problem then is twofold:
1. You want to carry them all with you... that's some weight & bulk!
2. When you're out with the camera you end up spending far too much time deliberating which lens to use.
So keeping lens choice simple can be the best way... for landscapes you generally have time on your hands so changing lenses isn't an issue which means prime lense are a great option... they're usually lighter, sharper, less bulky and have less distortion and vignetting. I usually just carry a 20mm, a 45mm and then for the longer end do throw in a zoom, a 70-200F4... F4 as I don't need the speed of a 2.8 which is a bulkier/heavier lens and actually has just as good image quality for landscapes where you're generally shooting at small apertures.
Coincidentally this guy has pretty much the same setup as me, worth a watch of the video... note too he mentions that limiting the focal range of lenses you carry can actually help with composition too!