Crusher run and stone dust are terms that vary from location to location and there is no specific standard.
Generally, you need fines in a range of sizes. Also coming from a manufactured stone plant (crusher, etc.) they generally are angular asnd will compact and be more stable once they are in place. A manufactured masonry sand might be an inprovement, nut natural mason sand would be all one size and rounds, so the stability is not there for this allpication, but is superior for use in mortar.
Just call a LOCAL aggregate supplier and get a price on what he has available for your application. You might find something better available a few hundred miles away, but the delivery of the material can be more than the actual cost of the material. They have rear end dumps that can have the back gate chained and dump it in a 8' wide strip if you are doing a driveway. (They back in and dump going out.