We didn't go out at all until they'd crusted over. But we live backing onto a field, so if we'd have needed to I'd have probably took her there as there's rarely anyone about. As long as they're definitely not going to come into contact with anyone then I'd say go for a short walk
You can still go out, when mine had them I still had to do the school run. Just kept distance from others
You can gk out for a walk. Just avoid playgrounds and other areas with lots of people.