radish is cool weather crop whixh means it would be all done and harvested before you even put the melons and squash in. I would not plant more than 1 row at a time on the squash (I assume you mean summer squash and not winter) and succession pkant it at least three time. Winter squash is not a great candidate for succession planting.

If you do radishes, lettuce likes the same cool conditions and is a great seller, especially heirloom types and green leaf. Radishes tend to get very hot and pithy in hot weather, an exception to this is the red meat/watermelon radish which gets hot but never pithy in hot weather

You should do at least 100 tomatoes of different types. Go heavy on the red beefsteak as they are by far the most popular.

green beans should be succession planted at least every 3 weeks and never picked more than twice as the quality goes way down after the second picking.

Are you gonna do things like beets and carrots? Both are gernerally very popular. How about herbs such as basil, cilantro and parsley?

I feel your pain, this is my first year market gardening as well. In the past, my garden was large enough for friends and family--this year it's an acre with other smaller plots spread around the farm. Boy, did I underestimate the amount of seed I needed. I know the people at the seed companies are laughing their heads off at my many extra orders. Stupid Me.
I noticed you left out sweet corn. But maybe you're like me and decided that the risks (violent psycho deer and Jap. Beetle invasions, space hog, etc.) outweigh the rewards. In my lurkings at the farmers' markets around here last year, new and fingerling potatoes sold real well, but it's probably too late to get good choices now. Banana Peppers, hot and sweet were popular, as was the sweet pepper variety Carmen if you don't have an aversion to hybrids. Peas and spinach are also reputed to be money makers in spring. Those guys, along with a variety of lettuce and radishes and speciality green mixes are how I plan to start my season.
But, yeah, being new to this is killing me too, but I love it. I love the fact that I have finally learned to drive a tractor, although I had plowed about a fourth of my field before my uncle (farmer for 80 years) comes rushing down and it becomes clear by the look on his face that there are some things you can't learn by reading about. But that was cool in itself, because now I know half the field is done right and I did it myself. Oh, I'm so proud. Now if the weather would just cooperate so Farmer Susan could plow the rest of her field I'd be in high cotton. Right now I don't like the fact that I just spent all day searching for a more energy efficent way to heat my makeshift shed/greenhouse only to discover at 12 o'clock tonight that if I hung plastic down from the loft, the inside temp raised 10 degrees right away. Note to self--keep little space heater--take back 200 dollar propane heater and never listen to that salesperson again. But tomorrow, I'll slap myself on the back for being a genius. Now if that irrigation system I pondered over for weeks on end arrives and works the way I plan...but there's fun in that too. I love this.
Wish you much luck this season, and may we both be successful at juggling all these little balls in the air.
Oh, shoot, sorry. Got off topic there and forgot--have you thought about investing in strawberries, blueberries or other small fruits? It may take a few years, but the end returns should be worth it. I'm starting out with strawberries and blueberries (hoping to add year by year) and plan to spend any extra time I have this season getting some land ready for bramble crops. And easy cut flowers, maybe?

Well I went to my first market meeting tonight and people looked at me like Im crazy with the amount Im planting guess they didnt relize how big my place is.

Well the reason I kind of decided against corn was that the area vrs profit. But my wife has kind of talked me into putting some in so I think it will happen.

They are wanting to start the market in april Ill probaly have nothing but fresh eggs to sale. But was thinking of trying to put in some Radish, Turnips, Beets, lettuce, broccli and cauliflower and seeing what happens.

I know one thing Im really excited and cant wait to go full steam ahead.

what zone are you in? okra is very easy to grow and produces well (in the right zones). I would also consider doing some kind of herb pots even what they sell at some of the upscale super markets, 3 inch pots with live herb plants are very popular (chives, basil, cilantro, catnip, lemon balm, thyme, rosemary, oregano are some that I've seen). Or of course growing them and then selling bunches of them would be great too. Basil is a super one too because if you plant a few that you never really cut, and let them flower, they are BEE MAGNETS, which of course would be a great benefit to your other plants.

What about strawberries? or blueberries? you can get those plants relatively cheap and of course the berries are very popular too?

zone 7b, I think to sale potted plants I have to have a nursery lic. But I will probaly do herbs also in the garden and do some heirloom items as well.

Your market meeting being surprised/shocked is probably because they know how much work you will be doing.

Start small. Specialize in a few things, not everything the first year.

I plant my radishes with my other veggies that are slower to germinate. It saves space and marks the row. I use ALOT of radish seeds, I use them to mark almost every row. I sell the radishes rather cheaply because I plant 1/4 to 1/2 lb per year. That's ALOT of radishes. Also, I plant radishes with my cucumbers and let them go to seed. Cucumber beetles don't like radish blossoms.

radishes are crazy popular at my stand, but probably not a good money maker. Have you considered sweet onions? I thought onions were too common, but I grow walla-wallas and they just fly off my table. beets and sugar snap peas are probably my best money-makers.

whatever you plant, furnish some simple receipes for the items on your stand that week. I started out with cookbooks.com and copied some receipes. You can't sell the receipes, but you can "give them to your friends". And this is how I tell my customers, "I can 'give them to my friends' and I hope you will be a friend of mine." it worked for me, especially for things alittle less common.

The most profitable items I have found to grow are raspberries, genovese basil, heirloom tomatoes and colored bell peppers. We give the basil a haircut every week and we get $10 a lb for leaves and some stems. The raspberries we sell to a farmer at the farmer's mkt for $3.50 a pint and he resells for $5. This year we will go to $2 for a half pint. Large variety heirloom tomatoes such as Goldi (a fantastic high acid golden tomato we get from Tomato Grower's Supply) Marianne's Peace, Brandywine and a beautiful (tho low acid) bi-color called Oxaccan Jewell help us avoid competing with the summer glut of low priced regular tomatoes. We get $3 lb for these tomatoes at an upscale grocery/deli and he sells them for $6 lb. Sunsation, an easy to grow yellow bell, Gypsy, a smallish but very tasty and reliable red bell and Hersey, a chocolate colored bell are easy to sell wholesale for $2.50 lb. All of these are grown without pesticide, chemical fertilizer or fungicide which helps the price.