Simple and easy, refrigerated one day in advance, using an incubator, just like selling ice cream in the streets when I was a child.

Buying a gasoline generator is small, but noisy, with a certain cost, and the cost will be higher.

If there are merchants or fixed power lights nearby, you can coordinate and see if you can borrow electricity.

Relatively speaking, the cost is higher, so you can purchase a snack car (cold drinks+fried ice and other items are put together, placed in a place with a large flow of people, and can be driven back and forth).

The specific situation has to be combined with my own experience. I have friends who have joined snack car, which is not advertising, so I don't leave specific information. For details, I can join Baidu snack car or snack car.