Crocal offers a custom Maintenance mode/Coming Soon page option. You will find it under Appearance > Theme Options > Utilities > Coming Soon. All you have to do is to enable the Enable Coming Soon tab and then choose whether you want to have a content only or a full page template of your choice for your whole site to be redirected to. You could make any page you wish with the style of your choice and relate it to the coming soon mode.
If you prefer to have always the site URL when it is under Maintenance (coming soon) mode, you can just set it as your home page under Settings > Reading.