I became an EMT-1 in 1978, spent almost all of my time treating victims of auto accidents. Of all the goodies in my state-issued kit, the things I used most were 4x4's, Cling (or the equiv), oropharyngeal airways, pocket masks, hard C-collars, and oxygen. Lots of oxygen. BP cuff without stethoscope (too noisy on the side of I-5, went for systolic by palpation). Almost never used big trama pads, air splints (before they took them out of the kits), stuff like that.

Obviously an O2 bottle isn't going to fit into your lightweight kit, so I think that if I was getting down to the lightweight nitty gritty, I would carry 4x4's, cling, a pocket mask (with one way valve or course), airways, one triangular bandage, and maybe a Sam splint and a couple of sanitary napkins. A BP cuff if you want, but at the EMT level knowing the BP is not going to help you all that much, 'cuz you can't fix whatever is broken. Paramedics and docs love to have a BP history, but way back in the boonies it isn't going to help all that much, because you probably won't have a paramedic to pass that info to for a long time, and by then the victim will probably be stable, better, or dead...