Here are some suggestions for travelling between resorts. There are almost innumerable possibilities, however, so get acquainted with your piste map, and prepare to explore.
Arc 2000 to Arc 1950: Take the Piste à Steph the very short distance, turning right to head directly into the village.
Arc 1950 to Arc 2000: The Cabriolet lift joins the two resorts but, if you insist on skiing, take the Piste à Steph to Marmottes lift. Ascend, then follow the Chalets piste into Arc 2000.
Arc 2000/1950 to Arc 1600: Go straight down to the Bois de l’Ours lift using the handy Piste à Steph. Once you have ascended to L’Arpette, follow the Arpette blue run all the way down to Arc 1600. Alternatively, ignore the Bois de l’Ours lift, passing it to the right onto Vallée de l’Arc. Follow the piste to the end, before taking the Comborciere lift. Then take the straightforward Mont Blanc run to Arc 1600.
Arc 2000/1950 to Arc 1800: Go straight to the Bois de l’Ours lift using the Piste à Steph. From L’Arpette follow the Arpette run for two sharp corners before heading onto the Grands Mélèzes piste after the Vagere lift. This will take you down to the Transarc base station. Otherwise, you can stay on the Arpette run before abandoning it for Belvédère near the Arpette bar. Jump off that piste on to one of many blue runs which go into Arc 1800 when you see the resort.
Arc 2000/1950 to Peisey-Vallandry: Go straight to the Bois de l’Ours lift using the Piste à Steph. From L’Arpette follow the directions for the run “L’Arpette to Plan Peisey” as explained above, continuing on Forêt rather than joining Retour Plan Peisey if you want Vallandry as opposed to Plan Peisey.