I am in what used to be zone 3b, but mid-summers here in the upper Midwest have been hotter in recent years, and fall comes a bit later. I start seeds in mid May to set out early June when I feel the weather is stable with no chance of frost. I will up-pot them if they look like they are outgrowing their pots, and have little set back in growth and don't feel they suffer much from root disturbance. Better than letting them get stringy and root bound. For the most part, I keep the potted plants outside in real sun, and only taken in at night for warmth.
I grow in the ground, but also put two plants each in a large black 15? gallon or larger container. I have super large used nursery pots from my niece who managed a nursery, including trees. The melons in pots mature before the ground plants.
I have tried a few cantaloupes, and have settled on Halona F1 as the best tasting and among the earliest for me.
I do have trouble with mouse/vole damage, often even on the small immature green melons.
For watermelons, Blacktail Mountain does well for me every year, and I've started to grow Crimson Sweet as well.
Some years the melons are sweeter than others, you can't really control rainfall or heat. Well, I suppose you could cover the melon patch with a tarp when you expected a downpour. My problem last summer was drought, all the rain went north or south of my dry doughnut hole.