Honestly, there is not a best route at all. Such a route just doesn't and can't exist.


However, a few personal preferences I can share here:

1) Take a long rest as soon as you have landed on the beach - ALONE!! You will have a sweet dream this way, which would otherwise never be revealed to you.

2) Rescue Karlach as early as possible, if you know how (navigate through Zelvor's cave to a high ground and then jump down over the river with your main character - Karlach will not want to talk to anyone but your main character).

If you wish, you can have Wyll jump down to talk to Karlach, which will trigger a special cutscene - not a duel, though, as Karlach is significantly more powerful than Wyll at the earliest point of time you may get to her.

By default, Karlach is by far the best damage dealer offered to the player this early in the game.

By default, Karlach does significantly more damage than Lae'zel can, having a more cheerful personality, whereas by default Lae'zel has significantly more ways to help out other party members.

By default, Lae'zel is born to be a party tank, whereas Karlach should never be used as a tank per se (she should always keep a short distance away from hostiles), even though most enemies would not prefer to target at her over others on Tactician mode.

3) Don't allow Lae'zel to go to the northern end of the Risen Road until you are level 5+. Otherwise, you'll have a good chance to be killed with no chance to fight back and may bring permanent death to Lae'zel.

4) Don't fight Antie Ethel until you are level 5.

5) Don't provoke or persuade Kagha to switch sides, for the best possible reward.

6) If you don't play with a race that can't magically put to sleep, such as Elf or Drow, you can have Priestess Gut killed by someone else, saving you both troubles and XP. You can still get the loot though.

7) Once the Goblin king becomes hostile, you lose all chances to recruit Minthara, unless you have already knocked her out in a proper way.

8) You can explore the entire Underdark and Grymforge, getting you powerful Adamantine armor/weapons, prior to dealing with Goblins or saving Minthara or Halsin or Tieflings. You have ample time in ACT1 to learn how to play the game in a proper way.

9) You can get to level 6 in Act 1.