LP hoses, not pipes?

Started work installing an Olympian Wave 8 in my 2014 Denali...found a few changes from how my '08 Jayco was built. First, the low pressure gas doesn't get distributed in copper or iron main piping - there's a rubber hose that runs down the curbside frame rail with manifolds wherever there's an appliance and other rubber lines run up into the trailer to the appliances. Second, the plastic enclosing the underbody is pop riveted on, not screwed on.

I'm planning to mount the heater on an interior wall toward the rear road side, nowhere near any of the manifolds or existing hoses, because it's the ideal place for radiant heat to reach the entire coach, and there's no other place nearly as useful.

So, my plan is to disconnect the existing bbq pigtail from its manifold toward the front and run a new flexible line back to where I will then drill a hole to run the hose inside and connect it to the heater, then seal/insulate the entry points. Since I can't drop the plastic underbelly, I'll drill a small shallow hole as a pilot and look inside to see if I'm going to hit anything important (unlikely in that spot).

What am I missing? The location is nowhere near any known plumbing or electrical lines, though I worry about the gray water tank...