SCROGGIN...to be eaten by the handfull as needed, Aussie or Kiwi in origin, both claim rights.
Sultanas
Chocolate
Raisins
Orange peel (candied)
Ginger (crystallized)
Glucose (barley sugar)
Imagination
Nuts
Imaginination section could include....yogurt balls, wasabi peas, dried :- mango watermelon or paw paw etc, seeds :- pine, pumpkin etc, licorice all sorts, fruit leather, M&M's, jelly beans or baby's.....make it salty, spicy, sweet or as healthy as you like, whatever you like to nibble on. Variety is the key.
Lunch usually consists of cheese & crackers, relish, maybe with a couple of slices of pepperoni, washed down with a 500ml vaccum flask of hot tea (winter) or icy cold flavoured electrolyte (summer). Ice lasts 6-8hrs in my flask.
I sit on whatever's available, but you could cut down a foam exercise/yoga mat from tesco's or similar...they cost only a few pound & weigh next to nothing.