It can be difficult to use a long telephoto for landscapes. The issues can sometimes be overcome.
1. Haze in the air shows up easily, so you must time your shots to minimize it, such as early mornings.
2. Heated air between you and the distant subject becomes more of a issue, once again, the solution is cold days or early mornings.
3. Just the amount of air between you and the subject means that the resolution is going to suffer, so don't expect high resolution.
In some cases. its the only option, but I would not want to try it on a regular basis.
Here is one image of the Alki Point Lighthouse in West Seattle taken from a moving tour boat at 235mm with my 7D and 100-400mm L on a cold and hazy day. I boosted the blues in pp perhaps too much because of all the gray.
I also tried to get a shot of Mt Rainier, but the hade overwhelmed it. Even trying to bring it out in PP didn't reveal much. Once again, the boosted blues to help the gray sky just colored the haze blue. The Mt Rainier image was at 300mm.