I started some seedlings here in April. I provided a nice mound (about 12 feet by two feet) with excellent soil and drainage. It took awhile for them to grow but now they are taking over everything (which is fine as I expected them to do). The leaves are huge and the flowers are numerous. The bees are as busy as (bees are) on the flowers. I have runners from the plants going everywhere (heck, they are trying to climb the fence, but I am redirecting them). The PH is about 5.5 and the water is dripped and constantly monitored as as I check the soil and it seems perfect. I am not overwatering or underwatering. I am getting about 6 hours a day of direct sunlight on the plants and about 3 more hours or more of indirect sunlight on these plants. I find that the fruit buds are forming after the flowers and getting to a size of about 12mm and then drying up and falling off.
Sounds like inadequate pollination or perhaps self culling to reduce the number of fruit per vine. Found this brief discussion via search.
"Fruit In order for fruit set, pollination must occur. Many growers have found adequate pollination requires the introduction of honeybees. Ten to 15 bee visits per fruit is key for adequate seed set, thus a marketable fruit size. This increases earliness, the yield, and the quality of the crop.
The fruit set of cantaloupe is cyclic. Several fruit are set per plant in each cycle. Only one to four fruit per plant mature to marketable size as the previously set fruit inhibit the growth of younger fruit."
The only clue I can pick up on, seeing as to how you're giving them good drainage in their hills, might be the pH. A pH of 5.5 is pretty acidic for most edibles.
In the 2nd edition of John Jeavons' book, How to Grow More Vegetables (there are several, more recent, editions available, but this is the one I own), he says:
"Most vegetables grow best in a slightly acidic pH of 6.5. A range of 6.0 to 7.5 is fine for most crops. When adequate organic matter is used, we have found crops will tolerate better a wider range of acidity or alkalinity." (p. 19)
But then again, Jeavons' definition of "adequate organic matter" is what most of us would consider "LOTS and LOTS of organic matter."
I don't know the soil type in Chico: is it mostly clay or mostly sand? Sunset (their Western Garden Book) says that cantaloupes like "light" soil. I know personally, from talking to produce buyers and sellers, that sand w/organic matter added is the preferred method. If this is what you have, then I can only guess that the pH--or something I'm missing altogether--is the challenge.
I think most melons just grow 1 or 2 mature fruits per vine? So those that dried up may just be the plants way of making sure just one fruit reaches maturity. You can try supplementing the bees with an artist's paint brush. Just dip in the pollen of male flower and paint the female flower and so forth. Good luck!