I suspect you already know the answer to that. A brand new dump truck would be clean, with a minimum of oil, grease, dirt, or grime. I'm sure you could construct a large enough accommodation inside the bed of the truck to have the equivalent living space of a medium sized sailboat.

The great part of this is, when all of your clothes smell like diesel/gazole/etc., people will assume you are a liveaboard!

You would have excellent security. If you had a "home invasion", a simple press of a button would disorient your attackers and incapacitate them much in the way of the wicked witch of the East. If they have ruby slippers, I believe they would be yours by right of conquest.

Also, you could park almost anywhere you liked, at any time. No one questions a dump truck being anywhere, because they have so many uses. With a prudent selection of magnetic door logos, you could park for a nap in the middle of Market Street in San Francisco, Fifth Ave in NYC, or right in the middle of Piccadilly Circus.

Yes. There are many uses for dump trucks and you would quickly get back your initial $1000, and any other costs such as storing it between jobs, servicing it, and so on.