Next June. Early June or late June? It matters, because the pass might not be open in early June next year. Highway 120 is a slow road, not something you can tow a travel trailer at more than about 35 MPH average over the pass. I did about 40 in my Honda CRV that I tow behind my motorhome. Then going down the pass towards highway 395, it is steep, second gear type of road, and you can burn up your brakes if you go to fast, and don't stop along the way to allow them to cool down a bit.
From Lee Vining to Zion NP, it is about 7.5 hours and over 450 miles, either going through central Nevada, or Las Vegas, then north on I15. Both ways are going to be really hot mid-June and July. Perhaps 100+.
Personally I would go south to Las Vegas, then spend a night there, then go into Zion, it is a quick trip, if you start at 7 am, you will get there in time to take in some of the Zion sites that day.
If you don't want to tackle Tioga Pass with it's 9,900' elevation, then back to 2,500' at highway 395 (this is a 7% downgrade) then the long way around is to return to Fresno, and take highway 99 south to Bakersfield, then 58 to Barsto, and on to Las Vegas via I15. It is a bit further around, but probably cooler. You can look up some of the cities on the Nevada route, and see what there temps are now, it will probably be close to that in Mid-June next year.
Good luck!
Fred.
Money can't buy happiness but somehow it's more comfortable to cry in a
Porsche or Country Coach!
If there's a WILL, I want to be in it!
I havn't been everywhere, but it's on my list.
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