Combining two indexOf and regex in to one
You were almost there. You can use pipe (a|b) to designate the regex to look for both a and b. With that knowledge your split is as easy as:

var name = 'Ron &amp; Peggy Sue and Darin Douglass';
names = name.split(/\s(?:and|&amp;)\s/ig);


EDIT: The syntax (?:...) is whats called non-capturing parens. These match the regex provided as '...' but it does not remember the matches. The problem with the simple /\s(and|&amp;)\s/ig/ was that the words and and &amp; would be matched. This new syntax 'matches' them but does not remember (i.e. report) them. Thanks to @cbojar for the pointer.

Also, there is no need to check for either delimiter in name. If none exist it will simply return a single-element array with name as its element.