Hello and welcome to the RTA forums !

You could actually drive the route described in 6 to 7 days in a business like fashion so that does allow you to spend a little time in places and perhaps mix the driving up a little to get off Interstate and see a few other sites of which there a lot to choose from. One area that has some great scenic roads and a number of National parks is through Colorado and Utah into Arizona.

1] Yes, as long as you are comfortable with it.

2] Boring is purely a state of mind and whether on 2 laners or Interstate there are always views and nearby places to stop at and 'smell the roses'.

3] Yes a couple of days spent on the Pacific coast Highway is worth it.

4] Yes if you have time, although not only would I drive across Death valley I would head north on 395 and enter Yosemite NP on route to SF, this would require an overnight stop and 2 would be better to enjoy these natural wonders. In Utah you will find the likes of Arches and Canyonlands NP and you could cut through Monument valley to the Grand canyon NP on the way to Vegas.

Much will come down to how much driving you enjoy and what your interests and goals are for the trip, but you can certainly have a great trip. Do a little more reading and open up a good map of the US and as you your trip starts coming together keep asking questions and we will be pleased to answer them.

Enjoy the planning.