Thank you very much UK flyer.
I did a United mileage run to Heathrow in November 2006 and
had a great Remembrance Day walking around the Westminster area (5 hours in London before returning to the US).
On March 30 I will be on the inaugural DEN-LHR nonstop in C, so I figure I'll spend a few days this time and get down to Paris (first time there). Will probably do the Fat Tyre day and night bike tours in Paris.
Anyways thanks for the helpful info and FAQ, looking forward to my trip.