If you have someone that will come by and check on them, just make it easy for them to dump a few crickets in once during mid week. Keep a small container, plastic tub with a piece of carrot in with the crickets before you leave and ask them to just place it in the tank open for a few minutes until the cricks jump out. They don't have to handle anything too disgusting.
Advice: get two frogs. They will be much happier.
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