Highway 99 north of Squamish is the reason this business exists: 40 km from a North Vancouver driveway to a valley with 300 m walls on both sides. Take it slow. The van is quiet at 70 km/h through the communities, and the walk into Joffre from the lot is 6 km each way over gravel — do it early, be back by two, drive twenty minutes up to Duffey and you’ve got the whole evening.
Battery math, honestly. The climb from Squamish to Duffey Lake is 900 m of elevation over ~60 km. Expect the 360 km Kia estimate to behave badly here — we budget this trip at 60% on arrival, which means charging in Squamish before you go up if you picked the van at anything less. Downhill you get a lot of it back and the van will tell you so.
The thing nobody tells you. There is no charging between Squamish and Lillooet, and there is no charging at Joffre. If you want to sleep at Duffey two nights with the fridge running and the tent hatch open, you charge to 100% in Squamish and you treat the descent as your refund.
Food. Buy in Squamish. The Duffey lakefront is beautiful and has nothing on it but trees and fish.