Vos currently leads the general classification standings after five stages, with three still to decide the first-ever Femmes champion.
The Jumbo-Visma star has one stage win to go with two second-placed finishes and a third most recently in the Vosges, but admits things may change in the mountains.
"Of course, you have to be realistic," Vos said after a difficult stage to Bar-sur-Aube.
"With the climbs coming up this weekend, normally, the GC riders are very strong and will take a lot of time.
"It's a different kind of racing on the weekend, but I'm very happy to wear the yellow jersey now."
Having built a 20-second lead over her closest rivals, Vos will expect significant attacks from the likes of Silvia Persico (Valcar-Travel and Service) and Kasia Niewiadoma (Canyon-SRAM Racing) in the coming days, with climber Ashleigh Moolman-Pasio (SD Worx) biding her time as the ascent begins.
Stage 6 - 128km to Rosheim - will likely culminate in a sprint finish not too dissimilar from Lorena Wiebes' (Team DSM) impressive effort in Stage 5, though stages seven and eight could see a much smaller number of riders fight to the finish.
Tour de France Femmes on SBS this weekend
Friday, July 29
Stage 6
22:15pm - 00:45am (AEST) LIVE on ŠKODA Tour Tracker
22:25pm - 00:30am (AEST) LIVE on SBS + SBS On Demand
Saturday, July 30
Stage 7
23:20pm - 01:30am (AEST) LIVE on ŠKODA Tour Tracker
23:35pm - 01:30am (AEST) LIVE on SBS + SBS On Demand
Sunday, July 31
Stage 8
23:25pm - 01:55am (AEST) LIVE on ŠKODA Tour Tracker
23:30pm - 01:30am (AEST) LIVE on SBS + SBS On Demand
