2000 didn't use any pathfinding for fire and police. Each station simply covered a certain area when it come to suppressing crime or fire. When it came to fighting disasters, the position of a station didn't matter. You could simply deploy police and firefighters wherever you wanted, instantly.

I don't know about the one long winding rail line being the best possible layout, but more realistic layouts worked very well. It's not surprising that a simulation can be gamed to work better with unrealistic layouts (e.g. search for "Magnasanti"), but a city simulator should work reasonably well with realistic layouts, even if it's not necessarily the best. Real cities surely aren't the best layout either.