3 or 4 of the generation 1 bodies will weigh a very large amount. I would not even consider doing that unless I had no choice, and was packing so far away from civilization that there was no option. Film backs are light, but they do take a lot of room. If you get a motor drive ALWAYS make sure you have a manual crank to wind the film. The battery in the camera will last a long time with just metering and letting the shutter go, so if your winder goes dead, you can still shoot with the crank. To that I would also suggest one Super body, it has a mechanical (1/60 second) shutter release so that again if all else fails, you still have a manual method to fire the shutter. Unfortunately the Super has the worst shutter curtain design, when the curtain mechanism goes, throw the body away. They fixed this in the Pro bodies.
My favorite motor drive for the gen2 bodies is the one that takes the 2cr battery. It is belt drive so nice and quiet, and also light because it has such a small battery. The 6AA grips weigh a bit more.
If you want multiple bodies, I would say to of the gen2 in the bag, with lenses and at least 2 film backs. That is going to come in at more than 20 pounds (I haven't weighed mine but it is at least as heavy as a 20 pound sack of dog food). Then keep additional bodies/backs/whatevers in the car in a hard case. If you are hiking with the gear, think long and hard about exactly what you need. Remember that the fisheye lenses weigh a very large amount, especially if you opt for one of the Russian lenses to save a few bucks. My 30mm weighs about 8 pounds alone (all glass lens elements). My bag normally has a SUper and Pro body, 3 film backs, sometimes 4 if I bring the 135 back, 55mm-110mm-150mm-210mm lenses, 3 extension tubes, one or two winders, one or two prisms, waist level finder (always have this), one or two manual film cranks (again always have one), a light meter, and sometimes the 30mm and 80mm lenses. If I'm really going for serious, the bellows lens shade will be in their too and sometime the 500mm f5.6 will go on the outside which is another 5 or so pounds with its case.
You can cram all that stuff into a pretty compact bag, but it does get very heavy. Add your tripod onto that stuff, and if need be some digital equipment and it's a lot to carry at one time. (my tripod is at least 10 pounds).