i agree that the bike shouldn't be modified; a bike like this is best appreciated in its original condition. if you wanted a bike to upgrade to more modern components, i would start with a frameset much more amenable to building up.

rod brakes are quirky. they are barely adequate in dry weather, and downright useless in the wet. they are a pain to keep in good adjustment.

it looks like most of your rod hardware is intact. you can get replacement brake pads from oldroads.com for not much money.