That is the advantage of "untethered."

Actually your configuration sounds pretty nice... perhaps the best reason for a separate power source is redundancy. And for that reason I would also have a CP AND a computer... not to mention the other tasks a computer can do.

Sure, it's nice to tie it all together... but as soon as you become dependent on those connections, something breaks.

As far as "protected from drops, being sat-on, water and direct sun," Greg was talking about a waterproof ruggedized machine... in other words, something that WILL operate in that environment.