Go to Home Depot to their cement and rebar department. They have wire mesh that is supposed to re-inforce cement walkways when they are put in. The wire has 6" squares, is 4' tall and, I think, 6' long. Bring the two ends together and tie the ends together with string so you have a 4' tall cylinder. The 6" squares allow you to reach through and pick your tomatoes.
Place the cylinder over the top of the tomato plant. Gently bend the stems to the inside of the cylinder and bring them up the inside of the wire cage and tie them in place. I use plastic grocery bags for plant ties. (I fold the bag flat, the I use a pair of scissors to cut across the bottom of the bag in 1' wide strips. They do the job and biodegrade in the sun by the beginning of the next planting season.)
Lettuce: Read the back of the seed packet. It will tell you how long it takes for the lettuce to be ready for harvest. You know how many heads of lettuce you need each week. Plant twice that many seeds.
If the beans keep flowering, they will keep producing. If they quit flowering, they will quit producing. Swiss chard produces all summer long. Tomatoes that are labeled "inderterminite" will produce until the first frost.
Get the Ortho book, "All About Vegetables" and the book, "Square Foot Gardening". I don't like the gardening books by Sunsett (not enough info).
Good luck to you and yours.
P.S. My tomatoes are just starting to turn color. They should be ripe in another week, maybe two.