In order to do that and provide an enjoyable summer for my kids, I have to balance a lot of things together. For example, unlike last year, I can't rent a car (hopefully temporarily, waiting for some bureaucracy stuff to go through) so whatever we do needs to be accessible by public transportation.
Then there's the fact that my back has been so terrible lately that I can't do anything that is labor intensive and that takes out hiking, which otherwise would be a great frugal activity for the family.
Add to that the fact that my children have gotten to the point where I have little kids and big kids and they aren't generally interested in the same things. My oldest two are almost 14 and almost 12, going into seventh grade and tenth grade and are teenagers in every sense of the word. Then my younger two are 9 and 7, going into first and fourth grade, and are quite children. They like 'playing' with their friends while my older boys are at the 'hanging out' stage with their friends. In short, they don't generally like the same thing so finding something that suits them all is tough.
And last but absolutely not least is cost. I have a lot of expenses now and to be honest, if I were homeschooling I'd wait with the trips until things were less tight. However, this is the only chance I get so it's now or never, so doing it now and trying to keep down costs.