I'll have to answer this in two parts.
I did it myself on a solo trip I took last month.
I was given a choice from a few countries and picked UK since I hadn't "done it" before.
It wasn't my favorite country from the ones I have "done" before (Germany, Japan, Mexico) but still fun.
I would expect that your kids would love it so much that you'd have to do it more than once.
When I played, I wasn't given the option of doing more than one country.
But you can always go and get another phone.
I said "done" in quotations, because I first did it when it was the Kim Possible game.
It's very similar, just more talking (it seemed) and different characters of course.
I played it with my DDs aged 8 and 12.
It was easily the best thing about WS and possibly all of Epcot for them.
They couldn't wait to play it again.
Sometimes I had to help them with clues, sometimes I didn't.