Thruxton Touring Spares

I'm looking at doing the Scottish North Coast 500 sometime this year with my son and a couple of his mates on various bikes. I'll probably take the Thruxton as I've got the luggage rack fitted now and it will be far more economical on fuel than my 'priller. Bearing in mind its a rather remote location (for the UK anyway) and the Thruxty has tubed tyres, would it be prudent to take a couple of inner tubes, just in case? Also would I be 'wise' to take some other bikes spares and if so what? I don't want to take the kitchen sink along, but I don't want to spend time at the side of the road waiting for my son and his mates to return with spares I should've foreseen I'd need.