I'm a big fan of finishing the day early enough to immediately shower and wash shorts, use the mostly dry part of towel (Im a skinny lad so use little of my towel on me) to do the "roll up and step on" trick to get as much water out as possible (letting the shorts hang a bit in shower helps a bit too) and then using sun and hopefully wind to dry them out.
If not dry in morning, I use second pair and leave them on back of bike, sometimes inwards, sometimes outwards, if on dirt road or dusty, inwards, if not outwards.

Outwards also is an effective "leave bike outside store" anti theft detterent.

dark side of tent, dark wall, all reflecting sun's warmth etc also helps drying, but getting as much water out as possible and time in dry air is the ticket.