I totally agree with your approach but
The rs232 connectors seem to work differently, some are more resilient to network issues than others (Link ones seem better). Over time I've become convinced the weather makes a difference, high humidity etc.
Dallas have this article http://www.maxim-ic.com/appnotes.cfm/an_pk/148 Guidelines for Reliable 1-Wire Networks
which talks about getting reliability but also shows how complex it can be to resolve. Just restarting normally gets it going again.
Unfoutuantly I'm not an electronics engineer so the level of testing suggested is currently beyond me, if i start using mango to running my house i may have to learn how so the heating comes on in the morning and i don't get moaned at !!!!