With well at 500 ft deep and water at 15 ft from the surface, you have about 300 gallons of water available in the 4" pipe. That is a full day of usage for most households.
A Goulds 5GS07 3/4 HP pump will deliver 1.6 GPM at 40 psi with water level down to 420 ft. The pump and motor together weigh about 34 pounds. http://www.goulds.com/pdf/7310.pdf
The production rate of 1.1 GPM should really include a depth to water at which the recharge rate was measured. A 500 well will produce more when pumped down near the level of the aquifer than it will when the water level is near the static level.
Poly pipe, 1" Iron Pipe Size, 200 psi rating, weighs 0.234 lb/ft. You can also get 265 psi rated pipe at 0.291 lb/ft.
Cable (12/2 submersible pump cable) is about 0.1 lb/ft.
The whole assembly will weigh about 200 pounds for a 400 ft depth to pump.
If I were doing the job I would figure that I could put it in to the full depth with myself and one of my sons, using the means described below.
The water in the well will pretty much balance the effect of the weight of the poly pipe when going down so the net weight will be close to 100 pounds when installing the pump.
Nobody here thinks of the rope as a safety device but it is a lot easier to control if you are lowering a pump because you can hold a lot if you take a turn around a solid object and let it slide. It is a little harder to grip the pipe and control it.
It's another story coming up. For that you would want a pulley and a couple of strong guys or a hitch on a vehicle.
If I were doing it I would put in two posts with a beam across them to hang things from and to lower the pump and pipe. The beam is a pair of 2x8's with a pulley or rod between them to hold the rope for lowering.
Run the rope through a pulley or rod mounted on the beam, and take a full turn around a nearby post, and you can control the lowering of the pump and pipe with one hand.
If you want to do it I will make a picture for you.