I think that's too defined as a solution. All sorts of people are going to be penniless for all sorts of unanticipated reasons. Rather than fiddle about with categories like "social security recipients", allow everyone to have a basic income, borrow against the future if necessary (look at interest rates), and hunker down (except for farmers, supermarkets, delivery people, hospitals and other essential people). We'd be done with it in three-six months if we did that. To me, that's likely the cheapest, quickest option.
Senior hours is a good idea. But hoarding affects everyone. I think rationing is coming. A run on food is worse than a run on the bank. Our local shop has no cans left, no pasta, no flour, no toilet paper. No medical supplies of the sort needed if you get the virus. Survival is the overarching principle, unless someone organises and enforces the common good.