Well just for clarification about position formulas.
Assuming everyone understand what coordinate system is, if not google it =P.
Silkroad uses 3 types of coordinate system a global (used to display position in players screen with origin (0,0) at jangan city), another one to reference player position according to their current zone (used for movement related task outside areas with origin (0,0) at the bottom left corner of each zone this is done for precision issues with big float numbers and performing operations with them) and another one for dungeons witch atm this moment i dont know much about it because i never messed up with it (but i think their are at the center of the model).
So to calculate distance u need to calculate distance from where u are to origin, plain and simple theres no magic involved.
To calculate a "correct" dungeon position it would involve calculating the position from jangan to the dungeon, then adding the distance from your position to entrance (assuming its a 1 lv only cave like dw) if it got more then keep doing the same as before to each lv.