We will be in WDW on Sept 9-19. On some days we will be arriving at EP around 3-4pm. What are the chances of snagging a 4th FP for Test Track or Soarin for later in the evening?
I would guess close to zero. I would get one for Soarin', and use the Test Track single rider line if possible.
We always go the third week of September. In all our past trips we were able to get a FP(using the old system) for test track and Soarin when we arrived at EPCOT in the late afternoon. They were usually still available until 3pm and sometimes as late as 5pm. Not sure if that will hold true with the new system.
My guess is it won't hold true. Remember you use to have to trek to The Land to get them. Now your first 3 you can get with the push of a button before the park opens.
You are going during one of the least busy times of the year, but even then a FP+ day-of available for Soarin or TT in the afternoon will be iffy. My suggestion is to book your 60-day-ahead FPs for Soarin or TT for the afternoon at Epcot. You won't have morning FPs for whatever park you are at, but since it is during such a non-busy period you should be fine with SB in the morning.
Arriving at 3. Does that mean you might do 3FP+ at another park and then hop to EPCOT? If so, when you arrive you just might IMO. Other option is do you really want the 3 choices? If not really-then schedule a noon and 1PM you don't mind letting expire-then a 3 to 4 Soarin you will use, then at 3:15 try for TT.
That's exactly the plan. We have 3 FP's for MK in the morning then we'll be at EP for the afternoon and evening.