I have no idea if grammatically there is any rule which makes a distinction between using "far from" and "a long way" in positive and negative sentences! Please have a look on my examples below and let me know if all the sentences sound correct. If not, then please let me know how should I "far from" and "a long way from" correctly:
- 1.1- The bus station is far from here.
1.2- The bus station is a long way from here.
2.1- The bus station is "not" far from here.
- 2.2- The bus station is "not" a long way from here.
To me, they all sound correct.