It should not be a big challenge for you to decide upon a location where you could be celebrating your child's birthday party. This is because there are plenty of options available to you and if you research online you will be able to identify some of the most amazing places where you could be spending time to celebrate all sorts of occasions including birthdays and anniversary celebrations.
You should ideally be going for a place that can cater to multiple requirements including sightseeing as well as gaming and other opportunities that you could be taking part in.
The one thing that you will need to be careful about is not deciding something for your family which they are not going to appreciate it or like it, especially your children, so, the best way for you to proceed would naturally and definitely be to decide together where you would like to have the next birthday party at, unless of course, you would like to surprise them with something of that sort.
However, surprises for birthday parties usually work best when it is celebrated at home or at a fixed location and it works better for adults as opposed to children who usually prefer pre-planning things of that sort.