Font del Truffe is located 6km northeast of Rocamadour, near Lacave.
From Lacave, take the D247 road for 100m (a strong left turn just befor the Ouysse river bridge). Continue on this small road for about 3 km. The entrance is on the left. Park just in front of it on the right.
Font el Truffe is on of my favourite cave dive. Once the very small entrace passed, the river goes thru a narrow and tortuous way. Coulours are very nice.
More information on Plongeesout.com:
http://www.plongeesout.com/sites/roussilon-pyrenees/lot/font%20du%20truffe.htm