Node B, F and I are sub nodes.
Node K is air battle node.
G & H are choice nodes.
Carrier Task Force is recommended for the better routing when taking on the boss.
Surface Task Force is favoured to clear nodes X and Y due to routing but with Akitsumaru you can choose either Surface Task Force or Carrier Task Force.
Use of Torpedo Cut In on high luck ships is recommend for the final kill of the boss.
For Hard mode, use of a high luck CA (ie: Prinz Eugen or Myoukou with torpedo cut in set up and a Skilled Lookouts is recommended.
Surface Task Force might be better for the survivability of you fleet for the last kill if your second fleet's ships are low leveled. However you will be fighting with the compass for the 25% chance to go from Start->E.
As last resort consider using Reinforcement Expansion to give your cut in ships a Emergency Repair Goddess which has a chance of bring them back to full health for the boss night battle