That is another great idea you have. However, if you do not want to deal with moldy vegies, though, I would suggest using the Fluker's high Calcium cricket diet and Calcium fortified cricket quencher. These one-two punch combo should gutload enough Calcium in crickets.
With the semiaquatic setup, from my understanding, is optional and unnecessary. A captive Budgett's frog will likely stay in water the whole time as long as they have enough water available. They do have the ability to travel on land, but I think they prefer not to unless they have to.