Some of those vines look long enough that if you put in a little patience and effort, you could move them to train up where you want them to go on the cattle panels. I usually have to take some time to train some stuff to where I want it to go too.

Really have too much growing together, that is how they grow, you can choose/ prioritize which food you want to get if the melons are not that important to you. You can try to improvise some more supports, but I don't see any real problem with just letting the melons grow all over the place for the summer. It may look like a mess, but it is just for the Summer.

Is that a hoop trellis? It looks curved. If you get watermelons growing up and over it please do post a later pic, I would like to see that! I've snipped off excess cuke vines in the past, no problems occurred.

Beesneed, never thought of that but that is a good idea. It’s really more of the crowding out each other is what bothers me, I’m worried with the lack of airflow it can promote fungal diseases and allow my plants to die earlier in the season. I was hoping they grow just taller from a single stem with minimal lateral branching but guess not how they grow.

Yes that is a hoop, I will post an update if the ever end up growing through the whole panel. Training them to grow vertically isn’t as easy I thought though!

I prune lateral branches most years and the main vine remains vigorous. I always wanted to do an experiment to see if when I trim back, does the main vine grows longer, are fruits larger, etc.? I don't have the space to grow multiples to do a comparison of pruned vs non-pruned. What I have noticed is that if I do keep one or two laterals, those have sometimes become the "insurance/back-up" vine when the main vine gets damaged, diseased, etc. I cut the main vine and I still have one or two laterals that become the main vine. This year I'm trying to see if I can keep it more compact by training the vine to go around and around on circular trellis surrounding the plant instead of straight up the usual trellis. I'm short and after 45 years of gardening, too tired climbing the step stool when the vines become too tall. If I go round and round, I'm hoping to keep the whole vine to under 5 ft. So far, I'm finding they don't like to grow in an upward tornado-style circular pattern - I'm using lots of ties every few inches to make winding/circular instead of straight up.