If you are planning a trip to a theme park or amusement park then you may want to consider spending the night there too. Lots of attractions and theme parks offer overnight accommodation such as Alton Towers or Disney Land Paris. It is fantastic if you are able to stay over, as it means you do not have to worry about contending with traffic on the exit or the drive home and often many places offer a free return or cheaper 2 day pass allowing you to be able to break your visit up over the duration rather than having to try and fit it all in on one day. Some theme parks are simply too big to go round all in one day.
Unfortunately the cost of these types of resorts is often quite high, even after you take in to account the discount you may be offered on the park entry. Some people decide to do this as a main holiday of for a special occasion such as a birthday or something instead of just a normal day out.
Ideally you want to stay as close to the park as possible, but somewhere just outside to allow you to get a room at a lower price. If you can find a hotel or B and B then try to book as far in advance as possible to secure you the best deal. Some will be able to advise you of other places to go within the area should you want to spend your second day doing something else.