So you lied to the man about "no rush" but you expect him to be honest with you?
That was meant to be a joke so don't get mad yet!
I am in complete agreement with
@Itali83 , if you can replace a window motor, an oil change is no issue. You do realize that an oil change and a fuel filter replacement are two of the simplest and easiest things to do to one of these trucks? The only routine maintenance that gets easier than that is...putting gas in the tank!
If disposing of used oil is a big issue just do what I do. Get a cheap garden sprayer, mix some diesel into the used oil. At night sneak into the your neighbor's front yard and use the sprayer to "write" in his lawn. Since my neighbor is an LSU fan, I write things like "Go BAMA" and "Roll Tide". The grass stays dead for at least a month and he stays mad for months.
You have to remember that there are a LOT of decent folks that work in and run mechanic shops. All of them are not trying to steal your money, in fact most of them are trying to do good work for a fair price. Many of us have at some point (myself included) worked for a shop. I know I personally treated each oil change, each tire or battery replacement like I was working on my Mom's vehicle and I would guess that most folks honestly do the same.
@SirRobyn0 runs an auto repair shop, that sort of man can be trusted to do The Right Thing. He could probably provide some insight into what a mechanic or shop manager wants to hear from a customer.
I personally like knowing how much oil came out of my engine, knowing how much actually went back into my engine, and exactly what container it came out of when I poured it in. There is something about watching clean, fresh oil going into that funnel that gives me a sense of happiness and confidence. Paying a little for maintenance instead of a lot for repairs...
Good luck.