No neutral if the motor is a 240 V load.

Cable does not count ground, so it will be labeled 14/2 with ground.

Cordage DOES count the ground conductor.
14/3 with white, black, and ground.

Your two wire pump has two hots and both must be broken by the pressure switch or whatever control you use, i.e. timer, relay etc.

Some areas now enforce three wire pumps & grounding requirements in well service. I am not familiar with code in your usage. Used to be water and steel well casing were considered ground.

Your service supply obviously should conform to code whether buried or overhead. Don't guess at conductor size and voltage drop. Determine the pump load at that distance and select ampacity within that range. Size the breaker to the load. IOW, hypothetically you could have #6 wire protected by a 15A breaker.

Consider running three wire w/g in the event you want 120V at the line/load connection.

No, breaking one will shut the pump off.

A service disconnect must open both hots, but there is no real reason to open both in pump control circuits.

That's true. The OP asks about the pressure switch, which breaks both legs.
If the service disconnect isn't at the pump hook up it's a lot safer to kill both hots before servicing the pump.

Save some money and use a single pole switch with a higher quality contact.

Any number of thew A/C condenser manufacturers have gone this route.

No more crappy contactor with copper contacts, but an actual single high quality relay contact.

There is no reason to open both lines in a straight 240 V circuit.

Yep, and no reason to have the expense of two contacts.

Ronnatalie, I can show you lots of pump installations with no service disconnect, only line breaker a couple hundred feet away in the basement or in the barn. Sometimes frugality isn't the best choice.