Back to the drawing board
I have finished work and had great intentions to begin the plan - 2 weeks prep, 2 weeks dispersing Caches then jumping in the boat and beginning. A couple of things have made me sit back on my heels and reassess.
I have got a good dose of the winter lurg that has seen me sniffling and hacking my way through the past week. It has truly dawned on me that Winter is not the time for heading to sea in a light boat. Feelings of vulnerability, cold violent southerlies, unsafe beach landings, boring beach walking and general unease with taking a packraft to follow the coast in winter have all led me to reassess.
Going inland over winter is also fraught with cold and vulnerable problems heading south.
So with much mulling I have decided to head north for the winter and commit to the southern portion as things start to warm up again.
The latest cunning plan:

It all looks a bit higgledy piggledy but is all doable in the time I have and now gives me a more sensible plan to work toward.