The current StoryRiver contents are stored in $:/StoryList!!list.
Here's a tiddler that defines two buttons...
one to save the current
$:/StoryList!!list field to a separate tiddler tagged with "savedStory",
and another to set the
$:/StoryList!!list from the list field in a "savedStory" tiddler:
<$button popup="$:/state/popup/savestory"> save story </$button>
<$reveal type="popup" state="$:/state/popup/savestory" class="tc-drop-down tc-popup-keep" style="min-width:auto;padding:0.5em;">
Enter a new story name:<br>
<$edit-text tiddler="$:/state/popup/savestory" field="storyname" /><br>
<$list filter="[tag[savedStory]limit[1]]">
or, select an existing story:<br>
<style> .savedStoryList { width:100%; } </style>
<$select tiddler="$:/state/popup/savestory" field="storyname" size="5" class="savedStoryList">
<$list filter="[tag[savedStory]]"><option><<currentTiddler>></option></$list>
</$select>
</$list>
<$button style="text-align:center;"> save
<$action-setfield $tiddler={{$:/state/popup/savestory!!storyname}} list={{$:/StoryList!!list}} tags="savedStory" />
<$action-deletetiddler $tiddler="$:/state/popup/savestory" />
</$button>
</$reveal>
<$button popup="$:/state/popup/loadstory"> load story </$button>
<$reveal type="popup" state="$:/state/popup/loadstory" class="tc-drop-down tc-popup-keep" style="min-width:auto;padding:0.5em;">
<$list filter="[tag[savedStory]limit[1]]" emptyMessage="no saved stories">
select an existing story:<br>
<style> .savedStoryList { width:100%; } </style>
<$select tiddler="$:/state/popup/loadstory" field="storyname" size="5" class="savedStoryList">
<$list filter="[tag[savedStory]]"><option><<currentTiddler>></option></$list>
</$select>
</$list>
<$button style="text-align:center;"> load
<$action-setfield $tiddler="$:/StoryList" list={{{ [{$:/state/popup/loadstory!!storyname}get[list]] }}} />
<$action-deletetiddler $tiddler="$:/state/popup/loadstory" />
</$button>
</$reveal>
To use these buttons, just insert {{StorySaver}} into any tiddler. Alternatively, you can add these buttons to the Sidebar by tagging the above tiddler with $:/tags/SideBarSegment. After tagging, you can reposition the buttons in the SideBar by viewing the tiddler and clicking on the $:/tags/SideBarSegment tag to display the list of tiddlers with that tag. You can then use drag-and-drop to move the buttons to the desired position in the list (e.g., above the $:/core/ui/SideBarSegments/tabs)