The Lot valley is magnificent. It is simply superb for biking. You can bike in the valley going downriver from Conques. That upcountry area is mostly forested and pleasant but not particularly special. It is absolutely, positively, worth jumping out of the Lot valley at Capdenac to go about 5 hilly kms north to Figeac, a very pretty town, and from Figeac, to go down the gorgeous Cele valley. The Cele (accents on both e's) from Figeac downriver is about as good as bike touring gets. Gorgeous limestone gorge scenery, little traffic, amazing houses built into cliffs, and a fine cave to visit, "Pech-Merle". At the confluence of the Cele & Lot, it is worthwhile backtracking a few kms up the Lot to St-Cirq-Lapopie, a beautiful medieval village built along a hillside. From St-Cirq, continue downriver to Cahors, another nice town. In Cahors, you're in the middle of a small designated wine region ("Cahors" wine), noted for its 'black' wines. The river widen not long after Cahors and the gorge disappears.
If you have time, the Dordogne valley north of Cahors between Bergerac in the west and Beaulieu in the east is equally fantastic for touring. Those two valleys, the Lot & Dordogne, form my absolute favorite region in the entire world for touring. I can give you names of places worth a visit. The whole region has a great network of quiet secondary roads. If you get yourself some good maps and choose your roads carefully, you will be in cycling heaven.