After getting my PF, i wanted to get airbags in to help with family trips pulling our popup (and bicycles and gear, there are 5 of us). I hated how the airline routed out of the bottom of the rear spring. I wasn't really interested in trying to slot the bumpstop or either of spring seats, so I went another way.
Anyone that has owned/driven a dually, knows how much checking air pressure can suck. Well, I bought a kit once that added a length of steel-braided line that extended the valvestem to the outboard tire. A quick visit to amazon yielded my two 9" braided lines. And I was also able find a pair of 90 degree bends. The pics show how clean it ended up. Multitudes better then the "Big loop" with the kit airline.
I hope this helps resolve some of those funky airline views.