I think it looks good. I can't help too much with the timing though. When I lived in TX it seems like we planted the garden around Valentine's day, most likely after, because I worked for a florist at the time so I was really busy with work for a couple weeks before. We didn't grow toms & peppers from seed then though. I'm sure someone who knows will chime in soon though.

You can also grow potatoes without building another sfg bed. Have you seen the potato bins (check Sinfonian's blog for instructions)? I have a small bin I built last year and I'm also going to try some in some very very large nursery pots I acquired recently. I'm going to try growing them in compost in the pots then mulch them up with straw.
They say you can grow potatoes in trash cans, totes, bins, beds, trenches or even a circle of wire.

Here is a link that might be useful: Tales of a Transplanted Gardener

Thanks for your feedback. I looked up the potato containers and may just do these 2 4x4s and give those potatos a try. Thanks for your help :)

The layout is good, although you could actually plant a few more onions in each square so that you could thin green onions out as they grow.

Potatoes are, IMO, best in a container of some type. Strawberries like their own bed if you're using perrennial type.

I can't help you with timing because I'd need more info about where your (zone 8 or 9) is at. :) I'm in 9b, but in FL. I'm sure that those in 9b in other parts of the country have different things with which to deal than I have.

TX A&M has a very helpful site, which will probably apply to some extent to anyone who gardens in a warm area. Here's one link, but just search and you can find answers to almost any question.
In this case, scroll down till you see Gardening Guides on the left. There are several guides to help you decide if it's too late for seeds or not.

Here is a link that might be useful: Aggie Plantanswers

Sinfonian also has some nice step by step type directions for the potato bin. Where's granny? Granny doesn't like the potato condo idea. Your layout looks great! You Southern types are making me hungry for salad!!

Here is a link that might be useful: Sinf potato bin

I'm here, Carolyn. It's not that I'm against the potato bins, I'm against the high rise ones. I think one that is three boards high with two crops layered in it is fine, but I wouldn't (won't) go higher.

Granny

Here is a link that might be useful: Annie's Kitchen Garden

I wish potatoes could be trellised..

EG (who has a trellis fetish)

EG, Trellissed potatoes give me nightmares. ;)