By air: Ryanair operates low-cost flights from Luton throughout the year to Nimes (Garons). They also have seasonal flights from Liverpool to Nimes and from Stansted to Montpellier (Mediterranee).
EasyJet have low-cost flights from Gatwick to Montpellier and another to Marseilles (Marignane). British Airways operates flights from Gatwick to Marseilles. Some seasonal flights to Avignon are now available on Flybe from Southampton and Exeter, and by Jet2 from Edinburgh (via Leeds Bradford).
Please note, the frequency and timetables of all flights are constantly changing.
A car is essential; rental companies are available at Nimes, Marseilles, Avignon and Montpellier Airports and also at Nimes Railway Station - Avis, Hertz, Europcar and others.
Transfer times by car (approx) to Mas des Figues, from Nimes Garons 3/4 hr, from Montpellier Mediterranee 1 hr, from Avignon 1 1/4 hrs, from Marseilles Marignane 2 hrs.

By rail a regular TGV service operates from Paris Gare du Lyon (just over 3 hrs) or from Lille (4 hrs plus) to Avignon or Nimes. The TGV connects to Eurostar at Lille

By road the simplest route is the A26 autoroute from Calais and the A6/A7 Autoroute de Sud through Lyon to exit 19 at Bollene or continue on the A9 to exit 25 at Nimes (West).
Instead, from Paris you can join the A10/A71 autoroute to Clermont-Ferrand, then cross the Central Massif on the A75 to exit 39 and take the N88/N106 over the Cevennes mountains to Alès; a spectacular journey. Alternatively, continue a little further down the A75 to the awesome new Viaduc de Millau, then cut across the lower Cevennes from exit 48 on the D7/D999.