Car rental and driving: Toulouse to Lot/Dordogne and then Lyon

In Toulouse, if you are staying close by you might find it more convenient to rent at Matabiau train station. Getting out of the city is not particularly difficult.
But if getting to Matabiau with luggage would involve a taxi anyway, you might as well head to the airport: it is on the "right" side of town to head to Cahors.

In Lyon, the airport is on the east side (opposite where you'll be driving from) and getting back to the city is expensive. Returning at Lyon Perrache train station is more convenient. The approach is a bit of a rabbit's warren of tunnels and ramps, but at least you do not have to drive in the city proper since the station sits right above the A6 motorway. Allow time for a few wrong turns, but it'll still be less time than driving all the way to airport and then coming back.

As for the area between Sarlat and Lyon... Auvergne is wonderful. If you have a spare night, you could spend it in Le Mont Dore and take the cable car up Puy de Sancy, for example. If not, in good weather you could try to stop at the Puy de Dôme cog railway on the way - I'd allow 3-4 hours for the detour, but with an 8 AM start from Sarlat it will work out.
So that you do not have an eye on the clock, in case you miss car rental office closing time: remember that car rental is priced by full days, so, assuming you pick up at, say, 10 AM in Toulouse, it costs the same to rent until 5 PM in Lyon as until 10 AM the following day. And they will gladly accept the early return the evening before.

If you did not intend to spend the first night in Toulouse it would have been easier to pick up the car at the airport and go directly to Sarlat (Toulouse-Blagnac airport is located on the right side of Toulouse to go to the Dordogne). You would be in Sarlat less than 2h30 later.

It will depend on where your hotel is but if you are staying in Toulouse the first night, except for the taxi, the easiest way is probably to take the shuttle bus which goes downtown.

As Balso suggests, the other option is to pick up the car downtown or at the Matabiau train station. This will save you from returning to the airport. From the train station you can easily reach the Toulouse ring road and then the motorway (toll) towards Paris

So, airport or train station, there is no better option than the other, it depends mainly on where your hotel is located.

And if you want to avoid a part of the boring (and paying) A20 motorway to go to Sarlat, about halfway you can take the small departmental roads leaving the motorway at Cahors (exit 58)

Thank you, Balso and JoLui, this is exactly the kind of information I was hoping for. I'm hesitant to drive straight to the Lot (we will have 2 nights in St Cirq Lapopie before our 5 nights in Sarlat) because we will be tired and if we miss our connection in Munich we could arrive fairly late. So we plan to spend our first night in Toulouse, at the Hotel Albert 1er. If we arrive on time, we will have the afternoon and evening to walk around Toulouse. The hotel is a 1 km walk from the train station. We could possibly walk it with our carry-on suitcases if it's level and there are smooth sidewalks, or we could just get a cab.

I have another question. I am trying to decide the best plan for our day when we leave Toulouse and drive to St Cirq. While based in St Cirq we plan to visit the Peche Merle caves, visit Cahors and do just a little wine tasting, and walk the towpath or other scenic and easy hike/walk. Will all of that fit into our full day there? And if so, would you suggest stopping in Albi in the way to St.Cirq Lapopie, or would that be too far out of the way? Or would you suggest another stop or just spending the morning in Toulouse and then heading straight to St Cirq and enjoying that area?

I should add that we like pretty much everything, from large cities and museums to towns, small villages and scenery.

Thanks so much.

To go to the Albert 1er hotel, you can take a taxi or the airport shuttle and get off at the "Jeanne d'Arc" stop which is the closest to the hotel (400 meters) There is a shuttle every 20 minutes from 5am to midnight. The ticket costs 9€.

If you pick up a car at the train station, walking there from the hotel is not a problem, it's a 15-minute walk and almost straight on 80% of the route. Take the avenue "Allée Jean-Jaures", it has wide sidewalks and a large central alley for pedestrians.

It is possible from Toulouse to go to Albi before going to St Cirq but you will have to leave Toulouse early because Toulouse → Albi is 50 minutes by the A68 motorway, plus the time spent in Albi, (parking, visit, etc) plus Albi → Saint Cirq almost 2 hours (only via small departmental roads)

Going directly from Toulouse to St Cirq will take you less than 2 hours via the A20 motorway.

So it's up to you, that being said Albi worth the detour. Even if you only stay there for 5 or 6 hours, you will have time to see the city and its cathedral.

If you still have some time left after leaving Albi, on the way to St Cirq you will pass Cordes sur Ciel which is also worth a visit.

https://www.la-toscane-occitane.com/en/towns-villages/cordes-sur-ciel