An awning tent is nice for giving a bit of privacy and protection from moderately wet weather. It wouldn't stand up to strong wind though.
On the way back I drove down the highway until about 4:30pm and then started to look for somewhere to camp before it got dark. Scanning around on Google maps, and using the satellite view, I looked for a track that ended without any houses near by. I found the place you see top right here which turned out to be a lovely quiet (free) spot for the night.
I did add the location to WikiCamps as it's clear people had camped here before and didn't seem to disturb anyone. While there's no signs relating to camping, there's also no signs saying that camping isn't allowed. There are probably many locations like this that can be slept at without causing any problems and modern mobile mapping is a great way to find them.
Here's the inside of the awning tent. It's big and airy enough to let me make breakfast without too much concern.
There is a sturdy ground sheet that can be zipped on to the walls to enclose the space.
I'm not planning to take the tent on every trip but will keep it for longer stays.