I am currently trying to keep a Vehicle Survival Kit to less than 400kg weight (mostly food and fuel) but this is for survival in potentially sub arctic coastal conditions for up to 1 year.

Kit weight is a matter of what is required to get the job done. Depends on the situation.

There are some practical limitations for myself.

Bicycle - Typically < 60lbs using a trailer.

Backpack - Typically < 40lbs during Winter