Start with 140 ft for 60 psi of water at the house.
Add the altitude drop to the well.
Add the distance to water, which may be more than the static level due to drawdown or aquifer dropping..
Add the dynamic pressure drop due to flow.
http://www.pressure-drop.com/Online-Calculator/ will help with the pressure drop, and then convert the PSI to feet by multiplying by 2.31.
However you don't need to plan for full gpm at 60 psi. As long as you have the gpm at 40 psi, that's good.
It's often easier is to use the tables that many pump books have, rather than the actual curves. In that case, mainly add the altitude drop to the well to the distance to water from the top of the well.
Here is an example table:
A 1/2 HP 1o gpm pump may be a good one for you. That size is about the cheapest submersible. Size the irrigation method and zones to match the pump. If you decide to get a 40 gpm pump to irrigate faster, it won't be so good for house water IMO.
If you will irrigate with long-throw impact sprinklers, then you would probably need more PSI.