Hi and good on you guys for having a go, Basicaly pack the BARE minimum of what you need to be comfortable and self reliant to a degree, then add what ever you need to that for the climate you will be heading into as needed [ have family or friends post it or buy it as needed ] ..
Usual story, least used stuff buried under gear thats used every day, emergency gear / first aid / tools / Fire extinguisher easily accessed etc..
Decent wet weather gear, battery or 12V operated drill / drills, with grinder disc attachments ..Assorted bolts screws to suit the tug and trailer, small roll of medium duty fence wire and good ole 100MPH gaffa tape and zip ties, Collapsable hacksaw, decent hammer ..