Is this possible? I tried it online, and everything seemed to work until the dreaded error page appeared at the very end. How many miles should something like this cost?

JFK-LHR (1st day)
LCY- EDI (3rd day)
EDI-LCY (3rd day - same day return)
LHR-JFK (7th day)

I did get JFK-LHR / LCY-EDI / EDI-JFK to price out at 60,000 miles--to my great surprise. However, we've decided we'd like to make Edinburgh only a day trip and return to London for a few days prior to returning to NY.