Any suggestions on places to spend one night during a drive from Paris to Monaco? We're planning on driving in early October, hoping to avoid all, or as many of the toll roads as we can, and stopping for one night on our way down.
Lyon is roughly halfway between Paris and Monaco if you are looking to stay in a larger city.
Are you aware that completely avoiding toll roads in France will add at least 4 to 5 hours to your driving time, which will already be at least 9.5 hours without any stops or traffic? There is an option on Google Maps to "avoid tolls" when you look up directions -- you will see the driving time go from 9.5 hours to 14-15 hours.
The majority of all "A" route motorways or autoroutes in France are tolled; if you completely avoid them and stick only to "N" and "D" routes you are going to increase your travel time by about 50%.
You appear to have not considered the train. Faster and cheaper, and for Monaco (where?) much more convenient. No tolls, and no parking fees.
Avoiding tolls entirely is not advisable on such a long drive, but a reduced-toll route can take you from Paris to north of Valence as follows:
A6-A77 to Dordives (small toll)
South on N7 to Cosne-Sur-Loire (excellent mostly 2+1 lane road)
back on now toll-free A77 towards Nevers
becoming N7 to Roanne, with a mixture of 2-lane and divided sections
N7-N82 to Balbigny where you take highway to St Étienne (small toll)
Saint Étienne is a nice and cheap place to spend the night (bad reputation but actually a characterful place)
Next day, some slow local roads (d1082 and others) will take you to Tain l'hermitage over some low mountains.
From there, stick to the toll highway as the normal roads will take, not 1.5 times, but twice as long. Except perhaps from A7 junctions 18 to 20 (montelimar to Orange Nord), where parallel N7 is excellent with few village crossings.