Gary Boyd Roberts isn't perfect. I share a Mauduit cousin with Peter Lawford.
The following is taken from pages 192-193 from The Royal Descents of 500 Immigrants by Gary Boyd Roberts, Genealogical Publishing Company, Baltimore, 1993.
1. Edward III, King of England, d.1377 = Philippa of Hainault
2. Edmund of Langley, 1st Duke of York = Isabel of Castile
3. Constance Plantagenet = Thomas le Despencer, 1st Earl of Gloucester
4. (illegitimate by Edmund Holand, 4th Earl of Kent) Eleanor Holand = James Touchet (or Audley), 2nd Baron Audley
5. Contance Touchet (or Audley) = Robert Whitney
6. Eleanor Whitney = John Puleston
Problem is that Eleanor Whitney's mother was Robert Whitney's wife, Elizabeth Vaughan rather than Constance Touchet.
Some very interesting and supplementary ancestors up her line but not as promised