Intermittently transmission will not engage

Sometimes transmission fails to engage, sometimes the engine won't start and sometimes engine starts and runs without keys when you connect battery? Suspect an electrical issue between ignition and shifter position? With a fully charged system ignition system works flawlessly except; lights in the dash and outside marker lights flash like a hazard would only at a slower rate and the transmission will just disengage and freewheel?
When it's not flashier it seems to be alright. But sometimes it will light up and when you turn the key, it will not start. If you go under the hood, disconnect the battery reconnect it will start and run w/o the keys in the ignition? Any ideas?