Personally, I'd wait until later in the summer and try for a non-holiday weekend visit if this is possible for you. Then more of the park will be free of snow and the roads open for sure. And possibly nice summer weather.
Have you Google Mapped it? It's a very long, and for the most part a freeway, drive and will cut heavily into your weekend (two days of the three).
Have you thought about where you will stay that night? Lodging options at this late date will be very limited.
Adding Florence into the mix (why?) complicates the itinerary greatly. I agree with Voyaging...wait until later in the summer.
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