I cook for my 7 kids on Sunday by putting a meal in the Crockpot at about 7am, then eating when we get home from church around 1pm. I never found a crockpot big enough (tried 2 pots, it was a pain), so I have bought a Rival 8 quart roaster oven, and used it as a crockpot, and it has worked great.
My question is this, can I use it as a roaster and slow roast cuts of meat and potatoes & vegetables in the same kind of time-frame? i.e.- put a roast and potatoes (dry) in at 7am, cook them at a low temp and have them done and ready to eat at 1pm? I looked in the owners manual, and even flipped through a rival cookbook which is specifically for roasters, on the store shelf next to the roaster, and it had nothing about slow cooking "dry".
I don't know the answer to your question, but I do have a suggestion -- try it! If it's done early and a bit dried out, heat up some gravy (envelope mix or jar) to cover it and add some moisture. If it's not quite done, serve some veggies while it finishes. Scrabble is a good game to play with veggies . . . If it's a disaster (unlikely), get out the ice cream, nuts, and dried fruits, jams (and chocolate sauce and/or marshmallow cream if you have it) and have a "Sundae Sunday". Or send out for pizza . . .