Your two year old would be free
If I were you I would check your township building for tickets. Besides tickets I got through my kids at school the ones from the township building have been the cheapest I've found.
The tours have various prices. Your best bet is to check the website. Hershey Park is a separate attraction with it's own prices.
Based on your description, it would currently be $67 for 1-day admission, per adult, during summer, without promotion. 2 years old and under is always free. I would visit the site for more details.
The Hershey Candy Factory is free for the tour. Not sure on the park. I think you can find the prices by Google of Hershey Park.
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