Hi
In addition to ur action plan which u have chalked out i would like to add few suggestions in approaching the crash issues..
The better tools will be something inline with MRTG or PRTG which can be very much useful to find out the amount of traffic being handled by the router interface.
you can poll up the router and get the bandwidth analysis in regular intervals.
Also you can monitor up the memory and CPU utilisation using those tools.
you can use show version command too to find out the possible cause for the last reload mostly the ios code mite be affected with some bugs which may be aso a possible reaso.
that can be overcome with an ios upgrade to a latest GD version available..
you have got enough links over here in cisco site which mostly deals with router crashes,buffer or memory leaks which also results in crash..you can use them up to find out exactly in which category ur case falls in ....
regds