I'm sure you'll be as delighted as me to hear that Aga cookers are very low maintenance and require very little daily attention. The key thing is to keep on top of any spills, as they are much easier to clean up before the spillage bakes on to the hot enamel.
Daily wiping is best done with microfibre cloths, one for cleaning and one for polishing to avoid smears. No cleaning product is required for daily cleaning.
For more stubborn staining the Aga is best worked on cold. It is imperative that any products that are used on any of the enameled surfaces are approved by the vitreous enamel association. Astonish is a good product for stubborn burnt on grease stains. It can be applied in a circular motion using a very, very fine grade of wire wool (always try a discreet patch first) or the end of a cork.
Internally, any cooking spills will burn off the cast iron so don't worry about this.
The cast iron doesn't require cleaning. When the Aga is switched off the ovens and hot plates may benefit from a wire brushing. Any excess food/grease that has been removed with the wire brush can then be swept out with a dustpan and brush.
General tips for keeping your Aga looking pristine