Playing, Anywhere?
What would it take for you to have a fully active setup outside?
Let’s say that I wanted to play in a parking lot, what would I have to have equipment wise to get that going?
How long is a piece of string ?
You are giving zero details about the size / scope / type of area / type of music / sound levels expected / is there dancing / is there a marquee etc …
Last time I checked no two car parking lots are the same.
I’d advise you contact a local sound Hire company .. give them the exact specifications of the area you need to fill with what level of sound and get a price for hiring gear for the day if its a one-off event.
Or you could just hire/buy 25k of Funktion One 
check out the Ion Blockrocker
we had a party in the middle of a park. had to run laptop off the battery but switched to my buddy’s halfway through and went for about 6 hours!
I’m talking equipment, just straight up, could I hook some gear up to a generator (IS THIS EVEN POSSIBLEY!??!?!) and then voila?
are you asking about the PA systems?
there are lots of articles here about that.
What would it take to play outside?
A permit
speakers
mixer/controller
powersource
if there is a need to get a permit. then get one
This or use your own speakers.
basically for the power source.
and this
We throw tons of outdoor parties. You will need a generator rated for the power consumption your using(speakers, lights, laptops, anything else)
At least 2 Powered speakers and a decent sub. A mixer to plug the speakers into and a table to put all your dj stuff on.
You will probably want a gazebo of some sort incase it were to rain.
Anything else would be to make your event more special.