Glacier Natl Park or Yellowstone

We will be in SLC in late June for a few days and thinking of adding on a few days at GNP or Grand Teton/ Yellowstone. For this, fast pace/highlights only is fine and playing things by ear. We will fly from SLC to either and rent a vehicle.

It's just a little extra thing to add on and only for 2-3 days. What's your recommendation?

A: Fly to JAC in the morning and paddleboard on String Lake --> come into Yellowstone through south entrance --> Old Faithful and Grand Prismatic

Stay in West Yellowstone

Next day Hayden Valley --> Grand Canyon of the Yellowstone --> leave through North Entrance, stay in Bozeman

BZN to home

B: Just fly to GNP and drive Going-to-the-Sun-Road. Make it a two day thing.

With Yellowstone the one-way rental car from JAC to BZN is a killer. GTTSR looks dramatic and incredible. But there is the slight worry it may not be open in late June.