DEN airside question
 

(I spent 10 minutes researching online but found no answer).

Are the concourses connected airside? If I'm flying F9 in A or WN in C, would I be able to use the UA lounge in B?

Yes, they are, you can take the train between each one.

Great! Thanks.

And the trains run every 2-3 mins between concourses.

Not sure exactly what UA lounge's written rules are at the moment, but the checkin desk does seem to be checking flights. Not sure if you were not flying UA whether you would get hassled trying to get in. Though if you try and are successful, please post back here.

TRRed

Current rules are the you only need a same-day boarding pass on ANY airline to use your United Club membership.