Is there a sentence fragment?
Spring and fall—the best times to enjoy the lake and avoid the crowds of summer. No fees or permits are required then.
A: no
B: yes
There is a sentence fragment that does not express a complete thought.
Spring and fall—the best times to enjoy the lake and avoid the crowds of summer. No fees or permits are required then.
Here is one way to fix the sentence fragment:
Spring and fall are the best times to enjoy the lake and avoid the crowds of summer. No fees or permits are required then.