Things to Check: Radiator over flow to see if it is higher than normal, Radiator and heater hoses, Waterpump. You will need a good light to try and trace where the water/coolant is coming from. If you have pets, keep them out of the garage until you have the coolant cleaned up. Antifreeze tastes good to them and can be very toxic if you don't have the environmentally freindly kind.

For the high idle, with our cooler fall weather the choke probably set the fast idle higher than you are used to and it picked up RPM as it warmed until you flick the throttle to set it back to normal.

Keep us posted

Pat