he's overtired - and a 3 yr old. Those are your issues. If what he is doing is getting in the way of life then force a change. Cup in certain place an issue? Start having "adventure lunches" where you eat in a different place every day (picnic outside, on the floor of the living room, in your bed, etc.) Cars parked just so, totally fine, but you can train him to undo this quirk. Make a game of it, tell a story to go with why they should today be parked over here, or just be silly as you do it.
LOTS of kids have these quirks, some need a little help to make them not overwhelming. If you don't work on it, you will end up with a much larger issue, if you work on it, and make him NOT allowed to get in those habits, then those habits will disappear.
As far as transitioning out of his nap, unless he's sleeping 14 hours at night, you are risking his health, his ability to learn, his language and as you see, his behavior. In fact even if he IS sleeping that long at night, naps are like oil changes for kids under 6 - you can skip them but eventually the engine (body, brain) will collapse and you will have a total melt down of skills and/or behavior. It may not happen overnight, but it will happen.