Well, I did another dump cake last night in my smaller dutch oven. So, two 21-ounce cans of cherry pie filling, one box of yellow cake mix, and one 16-ounce 7-Up.

This one worked a LOT better than any of my previous attempts - when I dumped in the 7Up, it fizzed right up to the lip of the dutch oven. I kept rotating the oven and the lid in opposite directions every 5-10 minutes. When I opened it up, it was turning nicely golden and some of the cherry pie filing was bubbling up through the cake mix in one spot.

So, I think I was previously only putting in enough 7Up to moisten the cake mix and make it a sludge...plus probably checking it so many times that it never got a good shot at heating.

As to the biscuits, I'd say benjammin's diagnosis sound correct again. I made my own homemade "Bisquick" mix, with the Crisco cut into the mix. I don't think the biscuit mix was too wet - it was just enough moisture to really knead it for a while to get everything moistened - not soupy or thin. I think I must have baked them so long that the leavening all gassed off as he described - they were not light and airy, but still tasty (especially with sausage gravy on it).

Thanks again for all the feedback - it's getting better each time.

Dave