Agent P's World Showcase Adventure

For Agent P’s adventure in Epcot, I have a few questions.
(1) If I pick up the device to start the hunt, must I immediately proceed to the pavilion to begin or can I stop for a meal and do a few other attractions before beginning the hunt?
(2) How long does it take to pick up the device?
(3) Which are the best countries to do?
(4) If I decide to do more than one country, do I have to backtrack to the beginning to let them know?
Thanks so much for the info!

You can use your own smartphone now or borrow their device. If I remember correctly, 30 minutes of inactivity stops the mission but hoping someone else can clarify. At the end of the mission, you will be directed to another mission of your choice and can proceed there directly. All of the missions (we’ve done most of them) were done well so whatever country is convenient or you are most interested in will be enjoyable.

Thanks for the info, @momfourmonkeys. Do you know if the 30 minutes start from the time you borrow their device/check in with them with your own smartphone or if you have to press something to start the mission?

I cannot recall. Hoping someone who has done this more recently remembers and chimes in. I do remember proceeding directly to our first mission, which was Mexico last time, after checking in but that may have been by choice (my kids love this) not necessity. The missions take 20-30 minutes depending on participants and if they want to look at other stuff, get a snack, visit the Kidcot station, etc. I remember that you have to choose your next mission at the end of the first (if you want to continue), but we didn’t rush off to the next country. I know we browsed the pavillions in between and then continued Agent P later.

We did the UK and found it a little long and drawn out abandoned half way so maybe we missed some really good steps. Did germany and it was fun with some really good effects. Did China and it was just okay.
Pretty sure that after one mission you can pick another mission right away, but I can’t remember. It’s been a year and there have been some changes.