I have ridden with my wife (115 lbs) and light luggage (beer) on the back of my 2013 DL650 through the NC mountains and had no problems bombing up serious highway inclines (going north to Blowing Rock, anyone? GREAT climb).
As far as electronics, I run a GPS, LED aux lights, a USB charger which I typically have my helmet and phone plugged into, as well as Oxford heated grips. I installed a voltage meter on the "dash" as I too was worried about the power draw, but while riding the voltage has never dropped below 14V with everything running. Sitting at idle, it floats at around 13.1V when I'm charging my phone or something.
The big bonus for me is a rock solid V-twin. I have shopped BMWs a couple time now and I get to the point where I'm all excited about the bells and whistles and then I imagine of the the bells breaking. And how much that would cost. At that point I thank Jesus for my V-twin and ride it back home, bell and whistle-less.
I did replace my front sprocket with a one-tooth increase which sacrifices a small amount of torque on the low end, but really opens the thing up at highway speeds. 90MPH has never been more comfortable!!