My best friend and I did this in June for his 21st bday. It was tons of fun and well worth the cost. Here's some tips and what I did (and saw others doing).
1.) Start early. It's not that you can't handle the drinking, it's just that I loved exploring the shops and taking my time enjoying myself. We started at 1pm and fit it all in.
2.) Stay hydrated. You know your own tolerance, but I found that a cup of water every 3 countries was what helped me.
3.) We took pictures of us in every country with our drink. This was a great keepsake and quite hilarious to see ourselves get progressively messier throughout the night. I've seen others have tshirts with checklists on the back that the bar tenders sign and other cool things.
4.) We started in Mexico with tequila shots. WIN.
5.) For those who like wine like me, buy a World Wine Pass or something like that for $20. You get two half pours in Germany, Italy, and France (most of the time they liberally pour more than a half.) VERY good deal!
6.) You'll be amazed of the amount of people who also do this! We met at least 6 other groups doing the same thing we were. Have fun with them and talk.
7.) We ended at the Rose & Crown with Strongbow and fish and chips. Best ending ever.
8.) Make sure those unexperienced with Epcot know how to get home. I'm not kidding here, people get crazy lost. For those with problems make sure they're with someone who knows what they are doing and write down on a map how to get out and what bus to take to the resort.
9.) Grand Marnier Slush in France. 'Nuff said.
10.) Have fun with the streetmosphere, especially the acting troupes.
11.) Explore. Walk around with your drink and experience the flavors of the countries. It's amazing what you miss when all you do are the main restaurants and rides.
12.) KNOW YOUR TOLERANCE AND PACE. This is the most fun I've had in a long time, but it can quickly go bad for those who cannot drink. We're talking quantity, length of time, heat, and walking. It's like a marathon, you don't train for the required distance, you run farther. Same here.
13.) Before you start get a Test Track FP and ride it when you're done. We called it "DUI" and was a big highlight.
14.) America has the weakest selection of drinks: only beer and not very good ones. Keep this in mind if you have non-beer drinkers going with you.
15.) HAVE FUN. Record your trip. Live it up. But BE RESPECTFUL. It's Disney and remember that not everyone else has 12 drinks in their system.
Salud!
