Why don't you just open it up, in a dark room, and aim a flashlight at it with the aperture set at its widest opening. Tape a piece of tracing paper across the film plane, and move the flashlight forward and back until the image appears sharpest. Even if you can't quite decide where that point is, it will most likely be just fine for your portrait distance. You can also change that distance by supplementing with positive or negative diopters, if you wish.
It is possible to get a fairly good (if imprecise) idea of what the focal length of the lens is in the same way, if you can get the tracing paper (you could use ground glass, too) to stay in a place ahead of the film plane. You would need a bright object a long way away, such as a streetlamp at night. Move the paper forward and back until you are confident that you have a pretty good idea of where the image is the sharpest.
I would not suggest using the sun for an infinity object. You could start a fire.
When you get that approximate focal length, you can measure the diameter of the apertures. Divide the diameter into the focal length. If you are right on, you'll get a familiar f/number. If not, you can see how far off you would be. The f/numbers will most likely be a three stop sequence such as f/11, f/16, and f/22. I'd suspect that is pretty close to what it would be.
One other way of finding essential information involves analysis of the probable tasks that the manufacturer would assign the engineers. What would they want the camera to do? Most of these cameras assumed a medium speed film, of ASA 100. Since it is Kodak, this would have been Verichrome Pan (which films do I miss most? That's one of them!). Figure that the camera has been designed to use the "sunny 16" rule. At best, the user will have limited success since the controls are so limited. The manufacturer wants the user to get the best success, because that will keep the customer buying film. So you can figure that they will try for a fairly fast shutter speed, and a small enough aperture to give a good depth of field. See if you can compare the shutter in the box with some other leaf type shutter; you can get rather adept at this but probably never will become a human shutter tester. I suspect that "I" will be something close to 1/100. If the camera was built for a lower ASA film (VP may have been 50 or something prior to it's life as 100, can't remember), it may have a slower shutter speed, but more likely, the f/#'s would be changed to one step down.
Regardless of which of the 3 apertures the user selects, one requirement would be sharpness out to the horizon. So, you could pretty much figure that the focal length / aperture settings would be designed so that the camera would be focused at the hyperfocal distance at the largest of the three apertures. That way, distant landscapes would be adequately sharp. The portrait subject could be closer to the camera than where the camera's fixed focus is set. You get more to the near side as you stop down, and you will "lose" some of your usable DOF but that's going to be inevitable.
This is the way us English major types do it (that isn't actually me, I was an art major! Worse!). The engineers will doubtless have some other ways to do it using formulas.
