You may also have the option of buying a day pass to the Delta CRC - I've heard good things about although never been in it. Pretty sure since they moved to A it's inside security, so easily accessible from the secure area of Terminals B, C, and D.

I also think Delta day passes are $25 but could be wrong

Also, I believe the US Envoy lounge has food whereas the general US Club between B and C is pretty spartan - makes RCC food offerings look like a complete meal the few times I have been in there!