If you follow the instructions, there will be no power drain unless you use an electrically operated brake system ( e.g. brake buddy or similar) Since you have a DP, I'd recommend a M&G brake kit. Proportional application, operates off the DP's air brakes ( no electric drain) and once installed, it takes only a few seconds to attach when hooking up the toad.
For lights, look on etrailer.... several kits to choose from. Here's one
hopkins tail light kit
Joe
2013 Dutch Star 4338- all electric
Toad is 2015 F-150 with bikes,kayaks and Harley aboard