The essence of TP runs is to garner tier points as cheaply as possible. Making a holiday out of it is an agreeable refinement, but once you restrict your search to a single departure point, then start adding qualifications involving exchange rates and your feelings about the quality and comfort of certain business-class services ...... it gets difficult.

Ruling out long(ish)-haul domestic US flights effectively excludes any reasonably priced TP runs from London. Sadly, RJ and Amman were ruled out of the game some time ago.

You might want to loo at double-TP holiday trips.