Did 2500 miles in 2 weeks earlier this year in a T5 VW Camper.
That was too many miles !
The VW was a 3 months old Californian, 4 wheel drive.
Just ate up the miles, brilliant over the Pyranees, through the Tarn Gorges, carried four bikes and all kit easily.
If you are hiring something make sure it’s up to the job.
Another time I would plan better each destination and use the motorway network to blat from one zone to the next, the tolls are worth the time saving and France is a big place.
Loads of campsites, no need to book.
We did however book the first night through the tunnel and the last night for the same reason.
Municpal campsites are a bargain, you may not get a swimming pool and restaurants but some were 20 Euros a night compared to 70 Euros on the meditteranean coast. (4 people)