Ok, not this year. A thank you to everyone for the information. I was a bit worried when I saw that Keystone had piled up materials on the supposed path (yes, I know that moving that stuff is not a big deal for those in the business, but still).
Sandcastle has been amazingly generous in ignoring bikers crossing their property (fortunately there’s enough space so that one mostly doesn’t get in the way of their customers).
Now that we’re transitioning into fall (and winter), folks should remember that there are other ways to get through that stretch:
After the ballast, turn right and cross the tracks, follow Baldwin Rd to the intersection with Glass Run Rd then a couple of rights to get you onto Riverton St. The car traffic is crazy, but the lane is wide enough to accommodate a bike with a decent buffer. Alternately, turn under Riverton and proceed through the Wemco property. If you pass on the left of the factory you can use their main entrance to get on 7th Ave. Alternately, continue (or round the building by the left) until you get to the end of the property, where you can see the auto parts store across the tracks. Cross (you’ll have to hoist your bike). Be mindful of business hours, so that you avoid workers and activity.
Go down 7th St then turn left on Amity St to cross into the Waterfront. Take the first right, which is the road behind the mall. Asphalt with light traffic, though ondulating for some reason. At the end you’re within striking distance of the GAP.