If you wish to do a five day run you have to realize that it's very different from a normal game. You have to save and reload a lot, not just to get the right NPCs but sometimes you have to get past a lot of monsters with powerful (ranged) attacks. (The most notable examples are the central room in the tomb of VARN where you have to enter all the codes and the large "entrance hall" in the Hive where you have to jump down and run to the central hole and "squeeze" through the bars).
Other than that it's a bit of planning and a lot of running.