Max. I think that route is pretty much it. The bridge at Kelley Point is fairly short, at least, so if you time it right you can avoid the squeeze.
there is one potential alternative, albeit illegal - aways after passing Kelley Pt Park, heading back toward St Johns, you can hang a right on Ramsey, go to the end of the cul de sac, dismount & hop the RR tracks if there's no train blocking it, continue on to Rivergate Rd., hang a left, and then bear right on Time Oil Rd. to where it dumps out on Lombard/Burgard. Can you spot the illegal part? Not sure if this is any more comfortable than the route you took.
I ride this generally on weekends/holidays and it's really quiet, no truck around at all as Terminal 6 is closed. Weekdays, as you discovered, are a very different story.