I usually just stake my tomatoes, but i found the video below ( and you have to check out his others). I think I may try his way using conduit, as its probably even going to be cheaper than splitting 2x4's as I have done.
Tammy

Here is a link that might be useful: Using conduit for trellising.

I think your absolutely right Tammy. Conduit is the way to go. It's strong, cheap, and lasts forever. It's all I've ever used and I wouldn't change it for anything. It's also strong enough to hold up at least 40 pounds of fruit(squash)with no problems. I've got pictures of it on my site.

Last year in a non SFG (regular garden soil) I used cages for my tomatoes, by the end of the year the tomatoes were to tall and I believe to heavy for them. This year with the SFG and the soil mix that goes with it, I do not think I will be using them them.

I have to agree that the conduit idea looks sweet, you can buy garden trellis and attach it to the frame that you build. I think this is the route that I will take this year.

Peppers don't need staking. They are strong and sturdy guys and if planted a foot apart and 'rub shoulders' they'll support one another fine. Save your trellis space for vining crops.
If you find they need support later for some reason (storm damage possibly), you can wind twine around them and shove in a stake to hold them upright.
I'd put all the tomatoes along the north side of both boxes, not one in front of the other. In southern climes they are going to grow for a long time and be huge so don't crowd them. They need air circulation to keep down the blight, etc.

i would reverse the direction of blue bed and trellis the squash put peppers up front.

I've tried staking my peppers with wooden stakes, using the inexpensive wire tomato cages, and doing nothing ... and I've had the best luck using the wire tomato cages. Last year, doing nothing worked through most of the summer for me, but come early fall, when the vines were long and the fruit most plentiful, I had entire vines (with nearly ripe peppers) snap off in thunderstorms. So this year I'm going back to the wire cages, just to be safe.

I hope you'll come back and post pictures of your tomato bed this summer. My experience with cherries is that they get gigantic and take over everything, so I'll be curious to see how yours do and how you end up pruning them. :)

The link below describes how I trellis my plants in a raised bed. All for the cost of some jute twine and some 1x2 or 2x2 lumber.

fwiw - for Summer Squash I allow a 4x4ft area, tho I do squeeze 2 plants in that area planting them 6 in apart. You could squeeze the Zukes & Squash in together but if they are Happy plants they will crowd out plants near them the way you have it laid out.

Those tomato cages are perfect for peppers or eggplant just not for tomato plants. Try the string method below. Just hope it's not too late?

Here is a link that might be useful: Vertical String Method