Personal tactics: For the Quickest Route, we basically go monster hunting to empty the route of monsters. This will probably extend time taken to 3~4 days, but an aggressive posture where we prioritize elimination of monsters is paradoxically safer due to rapid powerlevelling making subsequent monsters easier. If we get a 2-pick before hitting a Highly Dangerous, for example, it might now be reframed as somewhat dangerous instead. Instead of being interrupted by dangerous monsters, we would interrupt them.
This would also result in Letrizia getting quite a bit more healing, and overall we would have significantly more EXP by the time we hit the temple. Essentially, take the Quickest Route, but go through it slowly and methodically, hunting every last scrapf of exp. The style of an RPG gamer grinding exp..