you have a race result in the last 18 months that supports a 3:40? If so, print it and bring it to the expo. They move several hundred folks who did not get a proof of time into them in a timely manner.
if for some reason they are not acceptable, then running from your current location is the hand you were dealt. Starting from the back may feel a little aggravating for some of the first 6 miles. From the start line through the fist mile you will find room, even if its slightly grassy. The exit road into the parking lot is a necked down secgment so patience will be required. Once theourh the exit and onto the parking lot road, you will have a wide course; it may be tempting to borrow more than you should... Take the right hand side as you go through the toll booths. The road will neck down again around mile 2 for a small stretch then reopen near the aid station until the monorail station. Once in Epcot you will need to find your spot. Still kind of open but will neck down at Mexico as we head back stage.
Then around mile 4 we hit Epcot Dr again and you have a lot of room. Stay on the right hand side of the road to avoid exits lanes that keep dissapperaing on the left. Mile 5 will be a tough one for you. It is the first hill and many of the folks that you are still catching will walk it. There is room on either side of the bridge once on it, but beware that the shoulder disappears. Then through the clover leaf section and onto World Dr. it's wide and you can pass a lot of folks through the next 3.5 miles. Your crowd should start to thin out through this section; but you will find a back up at mile 9.5 the water bridge under the Seven Seas Lagoon. Once through that you have MK that can be interesting and just past MK is the stretch from 11 through 13 on a one lane road. You cannot go on the other side of the cones without risking traffic so you only recourse is course left. After passing the Poly you should have a little easier time for the rest of the race.