So im wondering,
1. Is there a way to drive to Quartz mnt Campground? ( believe its closed before that)
No. The roads are closed to vehicle traffic
2. Can I drive from 410 to i-90 and still stay in the 346 unit for the most part?
NO. You will have to enter unit 340 to get to I90. The 1701 is a border for 340, 342, and 346. At the end of the 1701, you will be in 340.
3. Is the best access from 410 or I-90?
I-90
4. Can I make it to the ridge at Pac Coast trail in a F-250 4 x 4 on the Little Natches road?
Yes. I have seen BMW's up there