Ignition key - kill switch?

[Ca160barnstormer]

Just picked up a dull-rusted beauty of a Baby Dream for myself. It started with one kick in sub-zero temps hooked up up a trickle charger. Shut off when disconnected. It does not have a battery or a ignition key/look cylinder. When I got it home I connected it to my own charger and started it up. When I disconnected the charger the bike kept running - I couldn't turn it off until I jiggled the (frayed ground wire) and other wires emerging from the frame.

I am looking for any advice on acquiring an ignition key assembly (will this act as a kill switch as well?) and a adequate battery (the seller said I could use a 6volt camping battery. Is this true/safe/reliable?).

Thanks in advance for any time taken to answer my post.