Mt. Shasta to Susanville

thanks everyone!

As much as I hate seeing a bunch of tree's being cut I appreciate what they did along a stretch of that route. It certainly allowed for more sun to hit he road and widened and added lanes.
I have driven that road over 100 times and have said when I die I want my ashes spread along it LOL!!
You should be just fine in Sept.

Watch out for deer. The most road killed deer I've ever seen was on that road. If you see one, start to look for the second and third, those are the ones that will cause you problems.

I travel this route frequently with a 36' DP towing another vehicle at that time of the year. Generally a good time to travel.

Most of the route is at 4-5000 ft. Reno is 4400ft.

That is the was we go to see our daughter in Portland. Good road. Weather should be good. Check first of course. If you have time and have not been there stop at Mt Lassen national park.

Good chance you will have fantastic weather. many places to stop and visit along that route. Don't be in a hurry if you don't need too be.
We will travel and camp in that area til the end of October.

About the third week of Sept. will be making our
way from Oregon to Carson City via the routes that connect Mt. Shasta, Ca., and Susanville, Ca. Was wondering if weather might
be a factor in the higher altitudes?

Traveled that route many times. No issues. Weather is usually great with high pressure, mild temps, and visibility 50-100 miles. On that route there really are no 'higher alititudes'. Farther south passes are 7000 -10,000 feet and even in the summer it can snow occasionally. It never last long and is not an issue. But the route you have selected is relatively low compared to other Sierra crossings. Wind is much more of a concern between Reno and Carson City.

September is usually a very good month for travel, we always do RV trips that time of year and on the route you have mentioned. We can get an early snowstorm but it won't last long and will barely stick to the pavement as the sun is still at a fairly high angle.
I would not let it stop me from planning a trip using that route.