The key to EPCOT these days is to get there at least 15-20 minutes before the park opens (longer during peak times). Work your way to the right side of the crowd by Innoventions West, and go directly to Tha Land and Soarin'. As with most high-demand FP attractions, I would recommend grabbing FastPasses and heading straight into the standby line. Depending upon your return time, you will probably need to ride back to back, so if you don't want to ride twice in rapid succession, just ride and standby and grab FastPasses when you get off or save it for another ride. If the FastPass return time is an hour or more after you get off, you should go to another attractions (TestTrack or Mission: Space).
I haven't ridden TestTrack since it was updated, but I've heard that the single rider is not as advantageous as it once was because you lose time in the vehicle design studio. I have heard, however, that if you want more time, you can do so after the ride or some CMs have allowed people to hang out in the studio through the next group. So depending upon how you want to experience the ride, I would probably still recommend the single rider line because using FastPass on Soarin' is more important.
Mission:Space would be next, and you don't need a FP for that one unless it's really crowded. If you're approaching your Soarin' return time, you could then go back over the the west side and ride Soarin' and The Land or head over to The Living Seas. Depending upon how much time is left until World Showcase opens, you might even have time for Journey Into Imagination, Spaceship Earth, or Innoventions.
Another good way to do those lesser Futureworld attractions is to wait until dinnertime when everyone is eating in World Showcase, and you can hit all of those right before Futureworld closes (usually at 7 or 8 PM).
Also on Soarin, expect to spend 45 minutes with Soarin (even with Fastpasses). It is the slowest Fastpass line in all of Disney World.
DO NOT get into line to go on Spaceship Earth as soon as you enter the park. Its a good ride towards the end of the day. Never a line!
Grab a showtime guide so that you are able to navigate around World Showcase. UK, Japan, China, American Adventure, and Canada have shows not to miss!
Make dining reservations (but you knew that :) )
On the left half, start by getting fastpasses to Test Track then head over to Innoventions East and ride Sum of All Thrills a half dozen times. Follow that up with a few rides on Mission: Space (orange) until your Test Track fastpass is ready. Then ride Test Track, followed by Ellen (sit towards the back on the right side for more time with the dinosaurs). After Ellen, head back to Innoventions East and visit whatever other exhibits interest you, then start your Perry the Platypus adventures and head back to the World Showcase (Mexico, Norway, China, and Germany). Leave the park mid-afternoon for a swim and nap, returning in the evening for Spaceship Earth and Illuminations.
For your second day (the right half), start with Soarin' (ride first then grab a Fastpass on the way out to use later), then visit the Seas Pavilion (take your time and explore). When your Soarin' fastpass is ready, re-ride it, then visit Living with the Land, Innoventions West, and the Imagination pavilion before heading back to the World Showcase, Canada side. Take a midday break at the Disney Boardwalk making sure to visit Beaches n Cream for lunch or a snack. Return to the World Showcase in the evening for dinner reservations and a repeat viewing of Illuminations if so inclined.
Best way to visit Epcot, imho.
As for the single rider line at Test Track, it's no longer than it was before. Yes, you stop for like a minute at most to pick out a car, but there's never a reason to slow it down.
Now the big catch about Test Track now is that the queue is really half the experience. Aside from setting up a very neat contextual mood for the ride and the idea's about contemporary and future car designs, half of the new appeal is the ten+ minutes where you design your own car. The control you have over this process is high and it's fun. Everytime I go I try to beat my previous car design scores. Having you car design on the ride it awesome, but what is better is seeing it on the leader board at the end and using you car design in all the post show activies, like racing it against other guest's cars, taking life sixe photos with it and making a cat commercial.
If you use Fastpass or Single Rider, much of the ride experience feels unexplained, out of context and even dull because you skip so much in the queue.
We will then go to the countries for a early lunch or light snack and then move on to the next park usally magic kingdom.
Every time I go to EPCOT I find something new. Last October, I toured an anime exhibit in the back of the Japan pavillion that I never knew was there. Those are the types of things that you will never discover if you just walk around the lagoon along the main path and just bolt to each of the main attractions shown on the map.
Walt Disney World's Magic Kingdom
Disney's Animal Kingdom
Disney's Hollywood Studios
Disney California Adventure
Universal's Islands of Adventure
Universal Studios Florida
Universal Studios Hollywood