I spend time trying to figure out which word fits best. 'Britches' sounds to common -- too hick for my character, 'breeches' sounds like something a fellow wears in a bodice-ripper, 'pants' sounds too modern, and 'trousers' sounds too stuffy.
I think I'm stuck with trousers, though, 'cause Roald absolutely refused to wear the kilt I offered to write into his wardrobe.