I think the responses are varying by climate and I think your rotors are doomed
The pulsing and grinding are the most noticeable symptoms but if you can get a look at the inboard side of each rotor you may see that side rusting up more completely. That "invisible" side of the rotor rusts faster because the spash shield doesn't allow the air to circulate as much.
I have seen rusting that reduced the shiny surface to about 1/2" radially on the inboard side of the rotor.
The only solution is to drive the vehicle more or store it in a dry garage.
I had that problem really bad on my truck. The rotors and pads glazed over after many cycles of rusty braking.
I got everything together and started a brake pad change when I discovered it was just glaze. The pads weren't very bad at all. I went ahead and did the change though - the new pads had a compound on them to break glaze and bed in the new pad/rotor combo.
In the future should this happen I'll just give the pads & rotors a quick lick with the flapper wheel to my 4 1/2" grinder to break the glaze and get everything right again.
Other than that, I really don't think there's anything else you can do to stop surface rust short of stainless or other type rotors.
Then again as little as you use the car you might want to oil soak the pads anyway, it will reduce rolling resistance and you don't hit them hard enough to worry about needing real strong brakes most of the time.
deer god please tell me you're joking cuz when little molly chases her ball into the street in front of you I doubt the judge will like that forensics found your brake pads were oil soaked and roters and wheels had residue with no oil leaks in evidence.
1991 Toyota Pickup 22R-E 2.4 I4/5 speed
1990 Toyota Cressida 7M-GE 3.0 I6/5-speed manual
mechanic, carpenter, stagehand, rigger, and know-it-all smartass
"You don't get to judge me for how I fix what you break"