The only thing I can ad is make sure you have at least 6 hours of sunlight so that your tomatoes and other goodies will ripen...
and remember to water frequently.
One thing about the upside down, or even elevated so the vines droop down: less strain on the stems, less spoilage from the vegies resting on the ground, and being out of reach of the turtles - who definitely like to snack on 'maters. Wouldn't mind it if they'd eat the whole tomato, rather than just taking one bite out of any tomato that they pass!
Check on the soil requirements. Tomatoes are rather hungry, and I seem to recall squash are, too. Using a 5 gal. bucket?