As with everything you do, safety is critical. Make sure you are working on a level, clear ground, and you have a second person nearby to help with ladders and spotting. Also, make sure any electrical cables are kept well away from water, and that you have switched off what you can on the inside of the van.
Make sure to apply the handbrake and chock the wheels to prevent the caravan from rolling away, then put down any stabilizer legs the van is equipped with to keep it stable and level.
You'll find a multitude of different surfaces on modern caravans; fibreglass, perspex, powder coat, aluminium, steel, vinyl, rubber & plastic just to name a few! The poorly sealed fibreglass of 20 years ago had a tendency to yellow with the use of older car care products - fortunately, our range is totally safe to use inside and outside of your van. Powdercoated materials are always ones to be cautious when cleaning, as they are usually porous which could cause staining if you allow anything to dry on them. Most caravans would have checker plate lining on the lower edges which are usually powdercoated.
We like to use a pressure washer for our detailing as it's much more effective and faster, but be conscious of keeping the gun well away from any vents or electrical components, and don't get too close to any silicone seams or edging to avoid damage. NEVER spray water directly into any of the vents, these often lead directly inside cupboards or behind fridges.