Many of the comments about the difficulty of putting Bilsteins in the front seem to come from the difficulty of holding them compressed while trying to insert them. I believe that Bilsteins are gas (pneumatic) shocks - so that their natural rest position when not mounted is the extended position.
I don't believe that this would be an issue with hydraulic shocks. If so, then hydraulic shocks probably would be a lot easier to front-mount on the E350/E450 chassis.
Top quality hydraulic shocks on an RV should match or exceed Bilsteins in performance, such as Koni's Frequency Selective Damping (FSD) shocks. Here's a link to them ... to understand how they work click on "how FSD works" down at the bottom of the page in the sentence above the last paragraph:
http://www.koni.com/car-racing/products/performance/We just completed a 10,000 mile trip with them on the rear of our Class C and what they did for bounce control, sway control, and highway crack jolts was spectacular - and this was from them being only on the rear. We'll have a couple more installed on the front in a few months - hopefully no hassle because they can be easily pushed or stretched into any length for front-mounting. Koni has FSD part numbers for the front and rear of the Ford E350/E450 series.