How about some electric Scissor jacks..
HEREA bit pricy at $62 each and they only are rated for 2K lbs each but in your case might work and make your life a lot easier..
I would suggest that if you go this route to have a wider steel plate welded to the bottom of the jacks and perhaps a piece of "C" channel welded to the top of the jack.. The wider base will make for a much more stable jack and the C channel will ensure the jack doesn't slip off the frame..
Use blocking under the jacks so you don't have to extend them very far, makes for a much more stable platform if you don't fully extend.
There are other scissor jacks which have electric motors so you could search and see if there is any that have a higher weight rating if your van is heavier than 8K lbs..
As someone else mentioned, try using some blocking under the tires to get it as close to level as possible then apply stablizers..
