I did the tour in 2010 and was told differing information from the tour CM's when I booked the tour and from the concierge CM's at the YC. Tour said I could go through IG early as they would let me in, but the YC staff told me no.
I did not want to chance it and took a cab from YC. It took 6min and cost around $8. The tour was fantastic! I just can not believe that staying at a EPCOT resort, you can not get to the front of EPCOT for this tour by walking. It makes no sense. I took a survey at the end of our trip regarding the tour and expressed my concern about this. A CM called me back and offered me 4FP's (FP-) for our next trip.