Hi Timothy. Thanks for the great question. It takes a park ticket to enter any theme park, regardless of the time of day. If you have already purchased a multi-day ticket, often adding a day can be done for a minimal amount, as the more days purchased, the less the cost.
Check out the ticket prices here to see if it's worth it for your family.
Our first night tradition is heading to Downtown Disney. Because we tend to arrive later in the day, we check in to our resort and then head to Downtown Disney. The shops are super fun, and get us in the Disney mood. There are so many great dining spots to choose from, we always enjoy a fantastic dinner and then it's back to the resort for a good sleep. And then we hit the ground running early the next morning. Wolfgang Puck Express, Paridiso 37 and Raglan Road Irish Pub are a few of our first night faves.
Another great option is dining at another resort. They offer a wide variety of restaurants at varying price points, and it's always fun to explore other resorts.
Hope this helps Timothy! Write back with any other questions!