A good deal of climbing and a good deal of traffic on many roads.
So I'm not sure what "experienced" means in this case.
My takes on less experienced needs - in order of importance - are:
1. Low traffic and/or adequate shoulders -
A high traffic road without shoulder can be tough - esp. when you have panniers on your bike.
2. Moderate climbing -
Really steep ascents - 10%+ - or killer rollers can really sap a new touring cyclist.
3. Frequent services -
New touring cyclists need the reassurance of services at moderate intervals.
4. Reasonable weather -
Extreme weather - heat/cold/rain - can really sap a new touring cyclist and make it a drudge.
The Nevada route has 1, 2 & 4 with good services until Fernley.
The Sierra Cascades route has more traffic and climbing, but better services and weather for July.
Camping options are somewhat limited in Valley towns.
And you will likely encounter few other cyclists.
PS - As for meeting folks along the way - after 20 years I have found that it is way better for them to meet me than me to meet them. Anyhoo, 60 miles is a hour driving for them and a day riding for us. It's different if I really want to visit Boulder or Jackson - - but it's even harder when it's a big city.