my current mostly pink skinned mare doesn't have too much pink skin in the "lighter hair" areas--nose and her teats are the only parts...around her eyes and ears is black. Sometimes when I roach her mane down, I run a bit of sunscreen down her crest where the mane comes out because I cut it short and you can see the pink skin pretty well. But I did have a gold champagne gelding, and he had pink skin all over, and until he really got the freckles coming in, he did burn fairly easy (both my current mare and my former gelding had a habit of laying flat out in the middle of the day in the full sun to nap). A bit of sunscreen on the more exposed areas did the trick. I used a childrens waterproof SPF 45. I also use it in the winter on my mare on her udders--the sun reflecting off the snow sometimes burns her down there (nothing like a sunburn in the winter! Haha).
Fly masks are a good idea to use too, and you can even buy the ones with the extended nose flaps to help keep sun off the nose. Flysheets, while I've never used one, seem to work for some people too. My critters are always chomping and chewing on each other, so I don't use them--but I have seen them for super reasonable prices.