You are up against and trying to solve the same problems we all have.
First you need to realize that the Prius has no strikes against it.
One mans trash is another mans treasure.
1. Curtains. Some people come up with ways to cover the windows along with choosing good places to park. It has to be learned. There is no rule book.
2. Space. Its an individual thing. Some people are even claustrophobic, most are not. The last thoughts in the Prius owners mind as she falls asleep could be of absolute joy as she has just cheaply traveled far and is even able to have the a/c running with out hearing a generator blaring away.
3. Noise. Its not just a Prius, its a van, an RV or a tent. Everyone is different. I have lived within 500 feet or so of a railroad track and at first it woke me up but after awhile I never knew it was there. I'm often wake up in my RV because the environment is always different.
If you want an established or given amount of noise every night you would most likely find it in a house or apartment or you need to be staying on BLM or forest land where you can distance yourself from others.
So with that said we still need to figure your situation out.
1. You don't want to be hot
2. I'm assuming you want to be warm in the winter.
3. It sounds like you want it to be quiet or reasonably so.
4. You want to play music.
5. You asked if the Prius system is the only one.
1. If you want a/c it is not practical to use batteries. Yes, it could be done but you don't have that much money and the system would be so heavy that its impossible to move. If you want a/c, you will need to be plugged in or have a portable generator.
How, where, who and the legalities of where to park and plug in are open for your research. Probably tough to accomplish.
Running a generator will work but it brings up several issues. Where can you park and run it as needed. It will need to be a Honda or Yamaha so as to be quiet. It will be stolen if you are not there to watch it or you will wake up hot one night and notice that you have found the quietness you like because someone else figured they needed it more than you. They didn't steal it, they reownered it because its ok to do that.
You cant insulate your way around this. If it was designed like a freezer or refrigerator, yes you could take it down to 40 degrees and shut it off and hours later it would still be cool but you cant get it down that low.
a
All a/c systems will only cool down X amount. If its 90 outside it will get you car down into the low 70's or high 60's but it will never get to 40.
Yes if you did accomplish this freezer/frig design you do need to ventilate it. You have to have fresh air. If it was air tight you would die. That's why kids used to die in refrigerators. Old designs had a latching handle that couldn't be opened from the inside. Kids playing would get in and couldn't get out. People responsibly started taking the doors off when they put them out for the trash man.
2. Heating is easier but still an issue. There are basically 2 types of heaters. Vented and non vented. Houses, RV heaters etc are vented. The exhaust/burn process is vented outside. The hot gasses move through a maze of tubing and vent outside. The heat that comes off those pipes is blown into the living area. Catalytic type heaters (Buddy is one brand) are unventilated. They burn very clean as far as the burn process is concerned but the fumes are still an issue for some as everyone has different sensitivities. They are not vent less because they need oxygen for combustion. They have low oxygen sensors to shut them off if the oxygen level drops too low. They are not intended to be used when sleeping. I and other people do use them while sleeping and we accept the risk. I have the windows open for oxygen so I don't really worry about it. I plan on going to a vented cat heater but for now I use a buddy.
The next problem with cat heaters is they don't have a thermostat so the amount you open the windows determines the inside temperature. Since the heater runs all the time at say 3000 btu you then have to open the windows enough so that it doesn't get too hot. I know, it sucks. If you say well I'll just start the heater a few times each night. OK that's fine but you should be doing it outside. I noticed people saying they dont like the start up propane in the air. That's probably because they are lighting it indoors. Read the manual.
This is the closest answer I have found for heating.
http://ventedcatheater.com/2.html
The only problem with it is that it uses 5 amps when the thermostat calls heat and the ignition coil glows. After it's running the exhaust fan uses half an amp to run the exhaust blower. Most of the heat stays inside because of its high efficiency so the exhaust pipe can be routed several ways because it uses pvc pipe and the exhaust fan blows the exhaust gas out.
3. Sound. Well, that is something that comes with the lifestyle. You need to adapt. That means get used to it.
4. Play music. You can play all you want but will it give you away if you are where you dont belong?
5. The Prius system. The Prius is a revolutionary car and a unique drive system that is not something that can just be used in another vehicle. Its too much to explain here.
You will notice that one of the core things that is utilized in this lifestyle is the ability to move from area to area as the seasons change. It's easier to save a dollar buy cutting out something wasteful or truly not needed than it is to keep earning more dollars. So its easier to move than to adapt to temperature extremes.
So this isn't for everyone and you need to build your system with a check list of things you can and cant accept. You may find that it wont work for you. It's overwhelming at times so you need to make informed non emotional decisions. Is there a plan "B"? What happens if the transmission goes out or the engine blows? What happens if you cant park at X place? I don't know what you have done so far but you may even pack up and practice camping or "staying" somewhere.
Good luck to you, you're not alone.
