Possible to run A/C overnight w/ battery charger?

No. The jump start terminals connect only to the 12V ("starter") battery. The A/C is powered by the high-voltage traction battery.

Leave the car in "Ready" and "Park" just as you did during the winter. Depending on the local climate this may well use less fuel than running the heater all night.

 

Well, you could leave the car running all night, but that's very inefficient. You can do a fair bit to minimise the heat build up in other ways, like parking in the shade, leaving the windows open a crack, that sort of thing. Or, you could buy a 2010 which has a 'pre-cooling' feature with an ac button on the remote.

 

With the electric A/C and the hybrid system, the actual fuel consumed while parked with the A/C ON is really quite minimal. I doubt that you would use a gallon (more like 1/2 gallon) just leaving the car in Ready overnight. The engine will be off most of the time, and will start up and run for a few minutes occasionally to top off the battery.

 

Find a hotel nearby would be better.

 

It's all about what you want...

1/2 gallon of gas 90 cents
Hotel room $35+

 

Any hotel room that cost me only $35 is a hotel room I would avoid!

In terms of energy consumption, chances are the hotel room would be better, but only because it already would be using much of the same energy. I've not tried the Prius as a camper bit yet . . . I'll have to give it some consideration!

 

Can you really sleep with the engine starting and stopping all night?

 

Yep.
I drove to Townsville from Adelaide, about 3000km and slept in the car. I did the trip in under 36 hours including rest time.
To sleep I had my swag rolled out in the back of the car with the seats down, put the front passenger seat back which made a good pillow. I applied the park brake then applied power in drive to load up the drive train against the park brake then pressed the park button, this stops the car shaking at start up and shut down. I placed a thick dark towel over the dash to suppress the light from it and sun shades in the windows. I slept comfortably for 4 or 5 hours, which was perfect. My swag has a 50mm memory foam mattress plus a 50mm self inflating mattress and a sleeping bag in it, almost as comfortable as my bed at home.

I'll add, I wouldn't be too keen to do this 2 or 3 nights in a row, 2 tops.

 

Sorry had to look it up:

Swag (bedroll), in Australian usage, a term for a portable shelter usually containing belongings traditionally carried by a traveller in the bush in Australia and New Zealand

 

Think a tiny tent. That is a tent just big enough for a sleeping bag with a person in it. My swag has 2 hoops of fiberglass poles to hold up each end but when I lay it out in the back of the car I leave the hoops out. Basically it keeps the mattresses and sleeping bag together. I also use it when camping out.