OP here. We had great luck in Macy's juniors department. Thanks for the recs.

My now 8th grader wore Athleta yoga pants almost every day last year. This year, they have a slouch pant she likes. Maybe try Athleta.

I wouldn't buy too much. She might be more interested in clothes after starting 7th grade and wanting to fit in with what the other girls are wearing.

Lands End in the Sears at Montgomery Mall (and online)

Macy's, Uniqlo, and Old Navy are my rising 7th graders go to stores.

I have some time tomorrow to take my rising 7th grade girl clothes shopping. Mostly, she needs pants for fall -- mid weight (not too warm) and comfortable. She doesn't care one bit about clothes (and neither do I), just wants comfortable pants. Where can I find a decent selection of sweat pants and other unstructured pants (she hates jeans and doesn't like leggings)? She wears regular sizes, neither slim nor plus.

Old Navy is certainly on the list, but where else? We're in Montgomery County.