If it helps, here is a picture of my veggie bed from last summer.

Here is a link that might be useful: My garden

Hi Tess, all of the plants you mentioned do take up a decent amount of space, so I think one deep is your best bet. I do follow a lot of the square foot gardening concepts, which technically say that one "large plant" such as tomato/pepper/bean/zucchini per square foot is OK, but in my experience planting them that close together has some drawbacks. Among other things, it means that the front plant would shade the rear plant. I would rather have one very happy and productive plant in a 2.5' deep bed as opposed to one happy and one struggling. Also, tomatoes, at least, probably need staking/caging/trellising, so you'd have to think of that as a consideration if you tried to plant two deep--I think it would be tough to find room in that bed for two tomato cages front to back.
What you could do is underplant your large plants with smaller ones like marigolds, lettuces, radishes, carrots, etc. since those types of things don't take much space and might appreciate a little midday shade on a southern exposure.
Good luck!

oh wow, the underplanting is a great idea. I'm a newbie, too, and we crowded most of our plants last year in our raised beds. Some did fine with it (like the swiss chard was still very productive - maybe because it grows straight up pretty much?) but others weren't happy (like the beets, but partly my fault because I didn't realize each tiny sprout was a separate plant). Our tomatoes were crowded and did poorly, but not sure it wasn't just the weather. The squirrels got most of the good ones. I think we ate 2 from 4 plants. The pattypan squash went crazy with vining, but very few fruits. I would not do anything that grows that big with such large leaves in a small raised bed again.