Is it okay to put a fence behind the cantaloupe as it starts spreading, and will it still grow well or up?
While you could do this, you would also have to fashion slings for each cantaloupe to sit in as the weight of the fruit would simply make it difficult for them to grow up the fence. Pantyhose works well for this.
I've read this excellent summary of pollinating cantaloupe [https://www.gardeningknowhow.com/edible/fruits/melons/hand-pollinating-melons. htm] but have to admit I do not see the pollen containing stamen. At the base of each male, they appear blunted (new, mature or old male flower). I'm positive they're male flowers and wondering if different varieties of cantaloupes have different appearing stamens. Example, all the ones on my plant are somewhat flat at the base. Any help would be appreciated.
The pollen appears as a powdery substance. If you are looking at a male flower, then you will see a yellowish powder. Whatever structure it is on, you can transfer this powder (pollen) to the female flower.
This article on telling the different between male and female flowers on squash applies to melons as well:
How long does it take cantaloupe to grow?
How do I know if my cantaloupes are ripe?
This article should help with that: https://www.gardeningknowhow.com/edible/fruits/cantaloupe/harvesting-cantaloupe.htm
My cantaloupe vines turned a little yellow and then I noticed the stems got small and just broke off the fruit before they were done growing.
It is possible that it got bacterial wilt. This article has more information:
How long does it take for the melons to produce fruit after planting? I have watermelons, cantaloupe and honeydew. They have already started to get the yellow flowers on them. This is my first time growing melons.
If you are seeing the yellow flowers, it will start growing melons soon. Melons have male and female flowers, like squash (https://www.gardeningknowhow.com/edible/vegetables/squash/female-male-squash-blossoms.htm). It will put out lots of male blossoms at first and will eventually put out female blossoms. If you see the female blossoms and immature fruit falling off, you may need to hand pollinate. This article will help with that: https://www.gardeningknowhow.com/edible/fruits/melons/hand-pollinating-melons.htm
I had transplanted Hale Jumbo cantaloupe in the spring. As in the past, my cantaloupes are small this year. They are the size of a softball. They taste good! Been to farmers markets and they have large cantaloupes. What do I need to do for next year?
Bigger fruit comes from better soil. This fall, when you clean up your garden, mix in large amounts of organic material, like rotted manure and compost. Add in some bone meal as well. The nutrients will have a chance to mellow over the winter and will be ready to go come spring.
Then, next year, make sure that your plants are getting more than enough water. Water stressed plants will produce smaller fruit.