There is an offline helper called "Tradewars Assistant" which has an excellent ZTM capability. It can establish beyond speculation about maximum warp length that certain sectors or clusters are orphans. It is available for download at
http://www.thestardock.com - Eleq's site. Filename TWAST23.ZIP, if memory serves.
After completion of ZTM, run the following in the twassist.exe directory, either from a dos command prompt or as a batch file:
twassist gamename.dat /A SN,1Y,allsectr.txt,a,rm
You have to substitute your game datafile name for "gamename" above.
It will write the text file "allsectr.txt" to disk in the twassist.exe directory. This file will be a listing of all the sectors in the game, in order of distance from Terra. Any sector(s) that show "???" for distance are orphans.
Takes 45 minutes or so for a 5K bang to run the ztm. Downsides of twassist are that it cannot work with bangs > 5K and you need to use a terminal program such as Telix, Telemate, Qmodem, Zoc, etc. to script the twassist I/O.