Either there is a lose connection in the radio, a wire under the dash, or the on/off switch itself is going bad. You would need a stereo shop to check it.
As far as running another 200K, the only thing I can recommend is be easy on it, continue the same maintenance schedule that you have been following. THe most important thing is keeping the oil changed and the engine running properly. Also, don't neglect the transmission. Make sure to continue maintaining it.