Where will you be hitting Utah?
What is a couple of weeks? Two weeks? 14 days? Or perhaps a little longer.
Running 80 miles per day over lots of mountain passes -
From Blanding you could do Utah in 5 days
PROVIDED you cut northwest from Torrey outside of Capitol Reef to Loa, Salina, and Delta then US 50. That saves about 80 miles or one day.
Nevada - 6 days from Baker to the east side of the Sierras
Calif - 3 days
But it gives you no leeway for the unforeseen - diarrhea, mechanical problems, weather.
And although you can't predict exactly what - something WILL happen.
Unless you are very experienced, I wouldn't think of doing this in 14 days,