I usually just fill DEF up at truck stops, seems a lot easier and less of a hassle, but I have 7 gallon DEF tank, larger than whats on the normal pick up trucks.
Id never consider OBA and bags without in-cab controls, for one simple reason...
When leaving the pavement and hitting the dirt we dump the bags to soften the ride.
It goes a LONG way in reducing vibrations in the camper, as well as in cab.
We run a simple, small 100% duty cycle Viair with a 3 gallon tank and a pressure switch, with in-cab controls.
I can monitor and control the compressor, tank pressure, and bag pressure(s) on the road, without leaving the vehicle.
Its not a kit.
But this setup is a great start.