The location is right at the start of the HDR file in the first 30 bytes. You need a hex editor not something character based like notepad. Notepad will ruin the file.

OK so find your location perhaps "Frosgardcity" and using a hex editor change it to another place like "Mountainpass". You must change the character directly following the name to a hex'00' or low value. This tells the game to stop reading the map name. So, if your in "lindisfarnemonastery" and you want to jump to the trainers just change the M of monastery to Hex'00' and you're there.

If you spell it wrong or forget to delete the .MM9 file the game won't load. But it's correctable, just fix the spelling or delete the .MM9 file. To verify spelling you can check in the MINISAVES directory. Also, as I recall, capitalization doesn't matter. Isleofruins and isleofruins and IsleofRuins will all work.