Eric said: “.. I should instead sit down (outside on a park bench if need be), shut up, and fill my head with pure dhamma for about a half-hour?”
Yes. Do whatever that works to get the mind off those incessant cravings.
Compare your effort to the effort of a baby trying to learn to walk. The baby will fall many times a day initially, but will fall and less as he/she makes progress.
In fact, that is a good way to check your progress. Do you fall less and less each new week or each new month? If so, you are making progress. Keep it up and you will feel the joy of not falling for a whole day, a whole week soon enough!