When your infantry are unloaded from the Sudden Transports, move them north-east. Shoot down the Cryocopters patroling the base perimeter, and then blow a hole in the wall and destroy the Power Plant. This will power down the Multigunner Turrets. Destroy everything in the base, and then capture the Pacifier FAVs and (optional) Multigunner IFVs. Then, you will get the objectives of setting up the Pacifier FAVs at all the ambush points and capturing the Steel Ronin by the Emperor's tomb to the east. Load your infantry back in the Sudden Transports and move them over to the Emperor's tomb. Garrision the Steel Ronins and move them in front of the tomb. Garrision the buildings up north with your remaining infantry. Then unpack the Pacifiers at the ambush points. This will trigger the arrival of the Soviet fleet. Target the forces (especially the Dreadnoughts) with your Pacifiers and blow them out of the water.
Despite being "ambushed", Soviets will quickly establish a base on the north-eastern sea, surrounded by ore mines, and another base west, on the main island. A barrack may appear north-west. The western base will produce land units and the eastern base produce naval units.
There will be a good flow of soviet traffic in the area north of the tomb. Holding this area will possibly thin out the soviet army and minimize harassment. Moving your tengus and steel ronins (and a few pacifiers) there will allow it to be done from the start. Placing a factory here will keep the units repaired and recover from terror drones (and pacifier friendly fire)
On medium difficulty, the soviets will focus more on capturing observation posts, occasionally attacking the tomb. Akula subs (and eventually dreadnought) will be sent to harass refineries and other base structures.
Both soviet bases can be attacked using naval forces. It is recommended to quickly attack the western base as it will eventually produce Apocalypse tanks. Hit and run to destroy key structures with a small force and shogun gunship should suffice. An attack with the initial force early on may also work.
Engineers can be used to repair the tomb. Removing the soviets will result in a win without having to capture all the observation posts.