I'm located in western Maine (zone 4, Oxford County) and I don't usually have much luck growing squash without giving it a lot of care, and then still not having a high rate of success. Short growing seasons with very variable weather doesn't seem to be all that good for growing squash in my little neck of the woods.
I cunducted a trial this past 2006 season with 20 cultivars (all "supposedly" easy to grow) to see which, if any, would survive and produce fruit without any care or human intervention whatsoever, planted in regular unamended dirt in an overgrown field. I figured that if any grew well there, then they should also grow well in my garden.
Anyway, there were 3 cultivars that passed: Connecticut Field Pumpkin, New England Pie Pumpkin, & Sweet Dumpling.
The 17 that failed were Autumn Gold, Baby Pam, Benning's Green Tint, Black Zucchini, Bush Delicata, Cocozelle, Costata Romanesca, Early Summer Yellow Crookneck, Golden Zucchini, Howden, Long Pie Pumpkin, Table Queen, Vegetable Spaghetti, White Bush Cousa, Winter Luxury Pie Pumpkin, Young's Beauty, & Zeppelin Delicata.
Hopefully this trial helps others in a similar situation.
I'd like to try this again next year to find more cultivars. Would anyone in Maine have any experience with very easy to grow squashes (summer & winter) that aren't listed above?