This really isn't an answer to the original question. The quandary is in not wanting or needing to have a laptop/desktop and being able to utilize just an iPad.
John, this won't be the ultimate solution you want (probably), but there are a couple of iPad apps which are able to edit RAW files. The only issue I have with them, is that they are nowhere near (in my experience with an X T1, anyway) as mature as LR is where initial edits are concerned. Which, yeah.. defeats the point really.
My question to the Adobe techs, if they're able to answer... is this: Who is responsible for making LR work on an iPad in the same way it does on a desktop? Apple, or Adobe? I've heard that LR mobile on an Android tablet would work as such.. so my assumption would be, Apple. But then, things aren't always black and white.
Doug, a few new Andriod cameras have adopted Adobe’s DNG standard. Apple has their own design, essentially using jpeg previews emended in raw files which are used in the Photos app. Even when using the Camera Connection Kit to get raw files on to the iPad, it’s necessary to set up preferences for the iCloud Photo Library to access the original raw files on your Mac desktop machine or laptop.