Just go south and destroy the Utsu... with a big spear army. Make peace with the Nagaoka. Ally with Nagaoka and the other Shogunate clan to march with you on Edo. As
long as you destroy or push back the immediate clans to the North it will buy you enough time to create a bigger army and reinforce your pacts for better protection. Hold off
attackers to the North for as long as you can and while you form a bigger army march through Nagaoka and take sado for it's gold. Pay a piece to Nagaoka and your bordered
allies more trust. Once you have enough money and men to defend you need to start farms. Try to complete this first part before the end of spring because there are no farms yet. (you start in winter) Then start your farms. Be wary because the Jozai have a low attrition rate even in winter. This will help you for your first year and what you do past this is up to you. Good Luck.