There are many clinometer apps available to help level your van. The one I use has a calibration button to set on level ground prior to pitching up.
a collection of top tips, tricks and ideas, DIY improvements and motorhome modifications that can also be made to caravans, campervans and RVs. Many of these modifications I have made and used on our own motorhome but I have also listed other tips, advice and product reviews that I have found on the Internet including ideas for day trips and visits.
Motorhome Mods UK 