If you are spending two full days in Epcot, there is plenty of time to see everything in Future World.
First day, go to the left, do Test Track at rope drop, then Mission Space. If you want, you could probably do Test Track twice, once standby at Rope Drop, then once with FP+. If you make your Test Track FP+ for 9:30 to 10:30, you should have plenty of time to do Test Track standby, then Mission Space standby, and then Test Track with the FP+.
After that, Universe of Energy standby (there is NEVER a line there) and then Spaceship Earth (might want a FP+ for this, sometimes it has a line). You should be able to get all of this done by noon, and head into World Showcase for lunch, and the remainder of your day.
Second day, go right, do Soarin' standby, followed, if you like, by a 2nd ride with FP+ OR . . you could use your tier 1 FP+ for Frozen Ever After later in the day, then Living with the Land, move on to the Seas with Nemo and Friends, and then Journey Into Imagination and the Pixar short film festival. You could probably even fit in another go on Spaceship Earth before heading out into World Showcase.
This is the strategy we use for Epcot, and it always serves us well.