Arranging posts in a custom order will be much easier if you use Meta Box plugin and the two extensions Meta Box Builder and MB Admin Columns. Compared to arranging posts by modifying the published date, which is time-consuming, Meta Box plugin and these extensions will do it more quickly in a blink of an eye for you.
We've just released v2.2.0 of MB Frontend Submission which has an important feature that allows you to customize the post submission form easier. This version adds the ability to reorder or mix post fields (title, content, etc.) with other custom fields. In other words, you can move post fields to any position in the form!