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Never tried it, but it's similar to elevation changes in CA mountains. Looks like a 3000' rise, so you would want to allow 30 more miles of travel or 150 miles of range needed. Then you want buffer of maybe 50 miles. I would guess an 85 could, would make it with no problem. Looks like the speed is OK. Here in CA, people think they need to go over the pass (6000 foot rise) at 75 mph, but luckily it's only about 40 miles and downhill on the other side.
I wouldn't go without a full battery. Or 95% on a 90D. Until you've done it and know how much it takes, take it easy.
I'm assuming, of course, there's a charger in Grand Lake.
Very doable. I use a 25% buffer for those situation and I am fine. I have to drive mountains everyday since I live in them! Of course, my lead foot doesn't help the range much...