As early as you want!! Just be prepared to wait until it starts if you are early.
One can show up as early as 1.5 hours before the venue. But Salt Lake City's Parking is usually not the best for events at vivint smart home. What I would Personally recommend is going early to get parking at the local City Creek Center, spending a little while there and then walking 2 blocks to the Thomas Rhett concert :)
I am sorry. No idea. I live in Canada
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