Calling all Van Chefs!

In our van conversion we have a Spinflo cooker, I don't find this is anything like as good as the Stoves cooker we had in our last caravan. But I'm persevering as best I can. What's the secret to get a good meal out of the oven with only one usuable shelf?! I've heard of some people producing Christmas meals, how's it done (we don't have room for a microwave either.) Or should I bother?!