You have a lot of space there so I am sure you can put a couple. The zucchini will spread, but you can probably contain to one per 2-4 square feet. You can plant 16 bush beans per square so you have plenty of space there. From here you can pick some smaller varieties of tomatoes or prune indeterminate to 1 per sq, or use other varieties and give more spacing. Google SFG plant spacing.

You will probably need to leave space for a path. Converting to two 3' x 10' beds (leaving a 2' path) may be good. You can also put in a trellis and train the zucchini up the trellis to save some space.