beartooth man.
This is the twin lakes headwall(where the lifts are, and they ARENT running this summer) on july 5th last year(and the snow year last year wasnt that good, and this year was, so it should be better).
heres the rest of it
Garner headwall is also good. Be prepared for some good hiking for both of those. I dont know if rock creek headwall will still have enough snow on it by then(in relation to the pictures above, rock creek had almost no snow on it when I took the pictures above). But you can do car laps with rock creek headwall, or at least hike back down to the road.
St. mary's glacier in colorado is always good and will have snow. I went there last year and had a good session with some nsers. We set up a rail and shit. Its pretty flat but is fun for summer.
If you want more info, shot me a message and/or search tgr for beartooth.