We have a similar revenue cycle model to the example that's included in Marketo's product documentation (see image below). Many of our leads come through the "Delayed" stage into "Lead." Given that this isn't on the success path, what is the easiest way to measure the conversion rate from "Delayed" to "Lead"? Please note that we do not have Revenue Explorer Reports on our account.
Without RE, this is a little difficult... Create a "previous status" field and make sure you archive status in this field before changing it to new values. then at any point in time, you will be able to create reports and smart lists on this "previous status" field.
You can also use the "Revenue Stage was changed" filter with old and new stage constraints, run the counts and compile the stats in Excel.
Right, RCE is the method here. However, if you happened to have a lot of time and fields, you could add Time Entered/Exited for each Stage along with a Lifecycle field that is synced to SFDC. Then you can run some reporting. But RCE or another reporting tool is the only real way to do this.