How about reinforcing the squash trellis with 2x4s or PVC hoops? I never care about how things look.
Could the squash be trained to flop in a direction away from the tomato, or are there other things already there?
>> do you think its better to have it try to compete for light against the vine on the ground
This is just my opinion, but I think the tomato would be much happier competing for light and root space than being uprooted and moved. But, again, let's hope for The Voice Of Experience, or even The Voice Of Informed Opinion, if no one here has a habit of moving tomatoes around after they mature and set fruit.
@NewYorkRita, what do you think about uprooting a 3-foot-tall cherry tomato and moving it? I thought it would usually kill the plant, or at least make it drop its fruit and flowers while it tried to recover.
Alex is in MN Saint Paul, so that might delimit how many warm growing days are left. Alex, when would you expect nights to go below 50F where you live?
I should also confess: I'm no big fan of squash, and I've wanted to try Black Cherry tomatoes for a few years now.