Assuming your criteria boil down to 1. Steel that is very easy to sharpen and 2. maximum edge-holding steels that also meet criteria 1...... and assuming 'very easy to sharpen' means it can be brought back to an effective working edge in the field using a hand stone in less than 10 minutes, then....
Vanax is probably the highest-wearing steel that is also very easy to sharpen. It is also virtually rust-proof. For a steel with such high edge retention and stainlessness, the toughness is also very good (though it is not a tough steel). But it is expensive and hard to get. But it would be the best steel to my knowledge for the two criteria above, so it would be my starting point. If you want to vary the criteria a bit, then....
If you want to retain ballpark the same edge-holding ability as vanax, but are willing to downgrade ease of sharpening a bit (along with stainlessness), then Magnacut, S30v, M390, 20CV, CPM-154 and Elmax would be good alternatives. This assumes they are run at a lower hardness than they're capable of, otherwise they can become hard (not impossible) to sharpen in the field. You wouldn't want to spend a lot of time maintaining their edge using river rocks and the edges of car windows however.
If you want to retain the same ease of sharpening and stainlessness as vanax, but are happy to compromise on edge-holding, then LC200N. It is also much tougher than vanax. But LC200N is relatively expensive and harder to find.
If you like LC200N, but want something cheaper and easier to get, and are willing to compromise on stainlessness to achieve it, then AEB-L. This steel is a bit tougher than LC200N and has exceptional edge-stability. Therefore you can run it very thin behind the edge, which will in turn increase its edge-holding (but because of the geometry, not because of the wear-resistance of the steel).
If you don't need stainless, then there are many steels that have good edge-holding and are relatively easy (not necessarily very easy) to sharpen - M4, CPM-4V, Vanadis4E, and the cheap and widely available 52100. (Again assuming lower hardness heat treats).
The caveat is that edge-holding and ease of sharpening are heavily influenced by geometry and heat treat (hardness), so there are more ways to meet your criteria than just steel selection.