If you want to keep these frogs for 4-5 days without any maintenance:

Feeding 4-5days per meal is ok.

Using misting sys to maintain humidity is ok.

I think the most challenging problem is how to keep the water clean. Adult RETF produce many wastes, it is easily to contaminate the water. The frogs are easily suffering from Red Leg syndrome or other diseases if contact foul water constantly.

If you insist to do it, I suggest keeping a small number (maybe 2) of frogs in the tank.
Fill the bottom of tank with water and use filtration sys. or putting several water bowl/tank on the bottom, in case one bowl is contaminated, there are several water bowl still clean.
Provide more plants, they may produce feces on the leaves not in the water.

You have green tree frog, right! How can you keep them during Apr-Oct?