I have ex officio, terramar & smartwool underwear - love them all for travel. Basic bikini or hipster style for women, purchased at Sierra Trading Post. Especially when they're having a 40% off sale.

I typically do laundry in my room and use towel racks or a clothesline if available for drying. Sometimes pants hangers with hooks (used last weekend in NYC). Had a great travel clothesline but lost it in a move ages ago and want to replace it. Ends are difficult though - suction cups aren't always going to work. Husband says just bring paracord and we'll tie it somewhere, which is our current backup plan ;-)

Folding "rack"? Not for me. I'm trying to pack light(er) and that seems like too much.