2000 Mustang Ignition Problem?

[Air Force One]

I have a 2000 Mustang, 3.8 manual, 90,000 miles but it has had a hard life prior to my ownership and needs some TLC. I have had it a little over a year and everything has been fine in spite of it's hard life. About a month ago I was driving it and I misshifted it at an intersection killing it and when I turned the key to restart it, there was nothing. I turned the key back to "Off" and tried again, still nothing. Back to "Off" again and tried a third time and she started right up. When I got home about 5 minutes later, I shut the switch off and the motor when off but the radio continued to play. I fussed with the switch again but could not get the radio to shut down. Of course this kills the battery requiring charging or jump starts after sitting overnight. It is not my primary driver so it sits for a week or so at a time. I charged and removed the battery but need to fix the problem. I suspect an ignition switch problem but before I trouble shoot by throwing new parts at the problem, any ideas to possibly pinpoint the problem?