We are also on a well, and typically can't run more than one
sprinkler at a time (the kind you connect to a garden hose) without
drawing down the well and kicking off the pump (our well was rated
for 5gpm and handles normal water usage with no issues).

Don't know what kind of sprinkler that is, but I tend to
doubt that the typical sprinkler on the end of a hose
is pulling 5GPM+.

I can run one sprinkler all day long if I want to. That's not a problem.
But if the sprinkler has been running a while and we use more water at
the same time (another sprinkler, wash the car, etc.), it can lower the
water pressure enough that the pump switch kicks off.

I'd probably put one of the pump protection devices on that detects
the pump running out of water and cuts it off, preventing the
pump from burning out.

Yes, that is the type of pump controller we have. Basically, if the
pressure drops below a certain level the pump kicks off and I have to
manually go turn it back on in the pump house.

Agree. It does take more water than most people would think.
A good place to start would be to calculate how much water
is required to cover the intended area with 1/2" of water,
which is a reasonable amount to put down for a watering..
If he uses 1 GPM heads, three or 4 at a time, that would be
3 or 4 GPM.
Then he can calculate how long it will take to water the
lawn and figure out if it's feasible. With a typical
controller you get 12 zones, which could then run
36 heads. Controllers that do more zones are
available. I don't know of any systems that use
the single wire approach and would think it would
be cost prohibitive as well as problematic.

More than likely, I would only install sprinklers for a few areas right
around the house. So, the total water load should be reduced
dramatically, and if I timed it to run when we normally don't use water
it shouldn't over power the well. Especially, if I spaced the timing so
the well had time to recover. Maybe one zone each day or something.

if you do go ahead with it,

I'm just looking into it at this point. I suspect the distances to the
power and water sources would be more trouble than it's worth for a few
zones around the house.

Odds are I won't have the time or money to do it anyway, but thought I
would investigate the options in case I decide to go through with it.

Thanks for the feedback!

Anthony