Okay, I searched the unit history of the 1st Armored Division and it doesn't have much detail about their action in this area---but they were organized into Task Forces and pushing north towards the Arno River Line.
I have a set of WW2 road maps of Italy. These maps are in 1:200,000 scale and there are 30 maps for all of Italy; I have about half of them.
Forcoli is just south of the medium-size town of Pontedera. Pontedera is on Hiway 67 from Pisa to Florence(remember this is WW2 highway identity). There are two roads going south out of Pontedera, the main one goes directly south from the west side of the town then bends back south-east direction. The smaller one proceeds from the east side of town on the east side of the Era River and winds along the river next to a ridge. Forcoli is about 5 miles south of Pontedera on this secondary road.
On MapQuest, this road is marked "Via Delle Coline" that goes thru the town of Val Di Cava before reaching the intersection near Forcoli.
Now you know exactly where it is.
Steve