I figured the LC+ was a good place to start, hard to go wrong with it. I know it runs well on DC, and there is no track signal to worry about.
Yes, it will have an on/off switch and a charging jack. I'll be lopping off the stuff they put on the charger and battery for my own connectors. While I'm at it, I might just include extra wire to allow me to have an operating backup light, I have to add a tether for the locomotive power anyway.