So the second option is cheaper and you get to go to Knoebels? Tough call. I suggest paying more to go to worse parks.
PS: If you find yourself walking around Knoebels thinking "f*ck Hershey's preview plan, I don't want to leave and I don't care about Hershey because this park is much better anyway" just know that this feeling is normal. The parks are only an hour and 15 minutes apart so stay until close. Life is too short to leave Knoebels early and do the Hershey preview sh*t. If you like camping (for some reason, lol) just camp at Knoebels and drive to Hershey in the morning.