I also advise not telling work. There are people who will treat you differently for any type of frugal choice....but this will be considered very odd and extreme to many people.
Investigate some of the 'stealth camping' forums and chat boards....there are a lot out of them out there.
If the van looks, from the exterior, like just another vehicle, you can cook/read/watch videos or whatever in one location and then just park in any neighborhood to sleep....stealth mode.
There is some safety in numbers though, so if you want a 'community' find the people doing something similar---there are in every city---and just observe for a bit. Perhaps they all hang out, cook, etc in one place but disperse for sleeping.
It is doable, depending upon climate, police vigilance, and your capacity to be flexible and 'read' your surroundings.
IT MIGHT NOT SAVE YOU MONEY over say, a studio apartment or a roommate situation. But, it can be done at extremely low cost.