Takeda clan

[Adrian II]

Even when I play Uesugi in the Sengoku scenario, I abandon Shinano on the 2nd turn, sweeping down into the Hojo Lands via Hitachi and Shimosa, usually eliminating them within the first two years.

With all due respect, don't you think it is preferable to hold on to Shinano from the start?
In order to do so, you have to withdraw your initial units from Hida and station them in Shinano. With two YS and two SA in Shinano, reinforced by new units and by your Daimyo if need be, you can hold out for ages and still conquer Hitachi fairly quickly (which is indeed necessary because of the Armoury, though Shinano has iron and sand deposits, too).
Hida will not be lost for at least fifteen turns, if not more, because Imagawa has been programmed to attack Shinano, Oda is too busy warding off Mori and Imagawa, and the Rebels in Kaga will leave Hida alone as long as you don't touch them. This way you will bring in much koku from Shinano and Hida, and have a chance to raise Shinano horsemen early on.