I think you are on the right track. Start inside: tomatoes, melon, kale, swiss chard, beans, ground cherries and most herbs. But even those will be staggered. In my CT cold zone 5 I started kale weeks ago, but wont start tomatoes till next week.
Direct sew:lettuce, carrots, beets, radishes, turnips. I actually transplant my lettuce but if you have limited starting capactity inside then direct sew it. Things I have sewed outside so far (under row cover): arugula, carrots, beets, radish, small white turnips, elegance greens)