An answer to your questions is not that simple. About tomatoes, it all depends upon what variety you plan to grow...According to my canning book:

50 tomato plants, planted in a 100' row will produce 380 pounds of tomatoes. This would yield 60 quarts of tomatoes (120 pounds) & 120 quarts (240 pounds) of tomato juice. Which it says would feed a family of 6 persons. But of course, each veggie would depend upon what a family likes or dislikes and all amounts would have to be adjusted up or down.

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Welcome Jason. I actually don't live that far from you. One piece of advice I can give you is to make the garden much bigger than you think you'll need so you have room to expand which will undoubtedly happen in the years to come. Above all else though, work on the SOIL first and foremost.

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John - Zone 6

roosterboy,
Like everyone else has been mentioning, it's hard to give exact amounts, but as far as potatoes go, (and, again, depending on what type you plant) each plant will usually produce about 6-12 potatoes. I've always grown the New Red Potatoes, and most of the plants give me about 6-12, sometimes more, sometimes less.
Good luck

Gizmo,
If you're wanting to buy plants (or even seeds) I usually go to my local Lowe's or Home Depot to pick up my tomato and pepper plants. They have decent plants.

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CajunMama
"Sing praises to the Lord..." Psalm 9:11