Thanks for the replies Otter and A/T too---good food for thought. I did get a small chuckle over Otter's thoughts--yes indeed why have it only to leave the cap in place full time?
So my biggest and perhaps foolish concern is over night parking where my paranoia is highest, even in my relatively crime-free neighborhood. I can't recall a vehicle theft close by in my 20+ years but that's meaningless in the overall scheme of things.
I do have remote-actuated deadbolt locks that makes entering the rear cargo area nearly impossible--short of sawing the hinges off there's no way to defeat them, the front doors completely unprotected. Other than a dome light actuated alarm they're vulnerable. The upside there is nothing of value is kept upfront and the dividing partition greatly limiting access to the rear. Even if crooks enter the rear from inside without knowledge of where my manual defeats for the deadbolts are located they're basically trapped inside.
That being the case and my thoughts of the hot wiring and driving away to part my van out at another location pops up. The Ravelco would greatly reduce that concern.
Most of my daily driver stops are short lived and I know that in and of itself isn't any sort of safety its not a huge concern. Its for that reason I'm leaning towards "hiding" the exposed part, perhaps another way to slow thieves down while the siren is blaring.
I didn't mention I use sun screens over the windshield and front doors, putting those in place has me working from the driver's seat for two of the three pieces, the final or right side requiring me to access the passenger's seat area. As such the best hiding place is near the fuel cut off switch. From what I understand most car thieves look for conspicuous things like the Ravelco cap or they'll fumble around near the driver's seat thinking any starter or fuel system kill switch will be easily found.
So my thoughts run towards if they can't even crank the van and can't see kill switches etc quickly they'd run away. I could be wrong but that's the way I'll proceed at the moment.
Still open to anyone's installation tips or experiences.