I just did a quick run through Lumbridge and made 200k. I started with Culinaromancer's Chest buying everything (up to the spices) except chocolate bars. I then bought all chocolate bars and smashed them into chocolate dust and rebought all the food that had restocked during the 10 minutes or so it took to grind all the chocolate. Then I ran up to the general store and got the free tinderbox and hammer (just for fun lol) and went to the fishing store and bought all the feathers and got the free items (again just because I was bored.) All in all it took around 13min and I made a little more than 210k. I'm not sure if the Culinaromancer's Chest items are really worth the time, but adding in the quick run to the fishing store adds another 12k or whatever feathers are. I also just remembered that I should probably note that I have not done the final fight part of RFD, which I would assume grants you higher original stock of the foods in the chest.