Brakes: may not be too bad. Was the parking brake on or off? If on that long they can bond to their drums, or cables can rust stuck - might break loose cleanly, but if chunks of lining are stuck to the drum you may need to replace the shoes and clean the drum. (The same can happen with a clutch on an MT car.) There will be rust on the disks and drum surfaces, but unless they’re deeply pitted (can happen under the pads where moisture is retained) this should wear off with use. Deep pits can initiate cracks, seek advice if you find any. If left too long the calipers and master cylinder can rust causing them to stick or leak, requiring resurfacing or replacement. It might be wise to change the brake fluid, especially if already old.
Other potential issues: the body corrosion you mentioned (inspect before making investments), check for mold/mildew (look under mats, in the trunk, the coiled ends of seat belts, follow your nose), bad fuel or water in fuel (drain and replace, be careful), change engine oil, change other fluids if old or you suspect contamination from condensation. Have you run the engine since winter? If not, you might try turning it by hand from the crank pulley nut or by pulling on a belt before hitting the starter - if stuck return to the forum.