Hi Mindy!
Agent P's World Showcase Adventure provides a great way to spend some time exploring EPCOT!
If you spend 20 to 45 minutes to do each of the "missions", which are currently available in seven of the countries throughout EPCOT's World Showcase, you would probably spend anywhere from 2.5 to 6 hours completing the program.
The World Showcase opens at 11:00 a.m., and, if you add in additional time that you will most likely spend in each of the countries taking in the attractions, restaurants, and scenery, you can probably count on spending the rest of your afternoon and evening completing the process.
The missions do have you exploring parts of each of the countries. However, we find that we definitely spend extra time exploring on our own, doing the things we want to do that are of particular interest to each of us.
If this adventure sounds interesting to you, I suggest you give it a try! If you find that you are taking too much time which you would rather spend elsewhere or in other ways, then just simply return your equipment at the next country.
Thank you for your question, and I hope you have a wonderful time in Walt Disney World!