'72 Scamp Can I just fix the front brakes to get it home?

My bad here, I didn't explain myself to well. I've done countless brake jobs on modern cars with power disk brakes, replaced rotors, pads, calipers etc.

I'm just new to manual brakes and drum rotors. What caught my eye is the master cylinder that shares the same resevor. Not sure if having bad rears will effect working fronts.
to a degree, yes, having bad rears will affect the front. you'll also notice an issue with the pedal pressure.

if you've not done drum brakes before it might be a little intimidating, but mechanically they aren't terribly complicated.

more than likely the rear cylinders are just blowed out. personally i'd just go ahead and repair everything and get it up to snuff, it's not like you're not going to need to anyway.