V3F

Are you letting the plants sprawl or are they on a trellis?

If sprawling, most people do put something under the developing fruits to prevent easy access by insects and to keep the bottom of the melon dry. If on a trellis of some kind, it's best to support them in a sling tied to the trellis. When they get ripe, they'll "slip" or fall off the vine without support. A split melon on the ground isn't what you want!

I think muskmelon ripeness is the easiest to determine of all the melons. They're ripe when they smell delicious and the stem separates from the fruit with gentle pressure. This is called "slipping". The netting of the Ambrosias will be raised and the fruit below the netting will reach a beige color as they approach ripeness.

As the melons get to be baseball-size, it's best to stop watering them during the final month or so on the vine. It allows the plant to use its energy to gradually increase the fruit size and develop flavor. I watered them up to the last minute my first year of melon growing, and they were the largest and most tasteless melons I ever tried. Learned my lesson that way!