How long will you be away and what time of year. Lack of food should not be the main concern but humidity. Worms can always munch and re-munch up to a certain point but lack of moisture and they're history.

Aside from a bit larger than usual feeding, you could leave several halves of apples. Or maybe whole apples with a knick. This way last longer because only a small part is exposed and the rest still protected by the skin. And there is moisture in them but in this heat, the bin will need some squirts of water now and then. I always had someone sprinkle the bins like 2x/week whenever I was away. No feeding because of my concern regarding overfeeding, heating up etc.

I have read about someone with a neat trick but some tweeking is needed before hand. He/she positioned a container with water higher than the bin surface and a string in it leading and curled it around the surface of the bin, taking advantage of the capillary action. My guess, the tweeking involved the thickness and length of twine to go around the bin which determines the amount of water the bin is getting. We don't want over-watering/flooding now, do we.

My hope, the worms won't start climbing the ladder in search of moisture.

Short answer: weeks and weeks if it doesn't dry out or start too wet. Is this indoors? Temperature excess - e.g. if in the sun - is the biggest risk; better slightly cool like in a basement than too hot. Slightly cooler will also slow down their metabolism somewhat - which will make food and resources last longer.

A thick layer of bedding on top will help keep it from drying out - slightly damp, but not wet. Also don't leave too much food - they are quite good at 'farming' finished vermicompost for leftovers so they are not likely to starve (bedding is edible too, eventually).