The tent hooks to the rear of the vehicle:@BerTX , that's an interesting scenario, and I would have never even thought of that. You could essentially create a climate controlled bubble.
Unfortunately I don't know any way to remotely bypass the restrictions Tesla puts on its Start HVAC command or any command for that matter. They have the final say as to whether they should actually go and start the HVAC, etc.
I am curious, when you start the HVAC then open the trunk, are you now able to send a start HVAC command with the trunk open? Or every 30 minutes you need to close the trunk, start HVAC, then open the trunk? Have you considered rolling all the windows down instead? Or leaving all the doors open, or does that have the same restrictions on starting the HVAc as the trunk?
As for USB ports active, are you positive that they aren't active with the HVAC on? Because I've camped twice now where I plugged in my phone and listened to music all night and it was charged fully in the morning, surely if the USB ports were not active my phone would have died. As is, automatic behaviors allows you to schedule any command to run on an interval of a few minutes, granted this lower bound is artificial, I could lower this even more but I don't want to push it. For now you could stagger multiple behaviors that do the same thing to achieve a faster interval.
I'll do some testing on both of these scenarios you've posed, I suspect there may be something we can do here.
I was trying multiple solutions, so I did not do extensive testing, but turning on a/c, then opening the hatch allowed it to run for 30 minutes, then shut off and would not restart with Dashboard. Running Dashboard with Camper Mode on did nothing. -- i.e. start a/c, start camper mode, open the trunk and it would shut off after 30 minutes. Camper Mode did not restart a/c nor did it give any kind of error message.
I don't think the side door being open trew the error, but I'm not certain of that. Just the trunk gave the error that a door was open. A door being open did not.
Fairly certain the USB ports went off after 30 seconds in all scenarios. They would sometimes come on when the car woke up, but the only other Dashboard thing that turned them on was opening the sunroof.
Actually I just realized I was looking at the 12v plug, not the USB ports (12v has a USB adapter in it) so need to retest that...