Spring peas should be planted early, "as soon as the soil can be worked;" in other words, no need to wait until all chance of frost is past, they like cool temps. Three sisters, as in corn, squash and beans? My feeling is that this is intended for field corn, not sweet corn - in my experience it becomes quite a mess with trying to get to the corn to pick it! Garlic is usually fall planted, so you should take that into consideration. Not sure what the "black bush beans" are, but are you talking dry black beans? In a limited space you will get a lot more "bang for your buck" by growing snap beans, a 10-15 foot row might give you a pound or so of dry beans, but can produce one heck of a lot of string beans; and you might want to grow pole beans as they will produce longer and give you a lot more for a given area than bush beans, as well as being a lot easier to pick. Best of luck to you, starting from scratch in an area like you describe can be difficult, and will probably take a few years to really get productive; but you will certainly feel you have accomplished something in the end!