Is the nonstop THAT much more expensive / more miles?? You are turning what could be a one-segment-and-done into a 24 hour ordeal where lots of things could go wrong.

That said, if I had to I'd do IAD over EWR on the outbound if you value reliability over lounges. Yes IAD / UA is a shabby dump, but it rarely has operational issues and at least you'd be in the same (but sad) C/D concourse for the connection.