Can I convert rich text field to have plain text output - with carriage returns?
Completely untested, but you should be able to do use something like the Craft-TwigPCRE plugin and some variation of this code:

{% set text = "&lt;p&gt;Some text&lt;/p&gt; tags as well as stuff like &lt;strong&gt;.|preg_replace('/\&lt;p\&gt;/', '') %}

{% set text = text|preg_replace('/\&lt;\/p\&gt;/', '\\n') %}


\n is the Line Feed control character for Unix/OSX.