395/44/89 is my backyard.
395 between Bordertown and Susanville does not have much in the way of services -- 1 gas station in Doyle.
Between Susanville and Mcloud there are not many either. Slightly off route in the community of Old Station (where 44 & 89 split) 1 gas station. 2 miles off route at the 89/299 intersection is Burney -- a full service town. Between Burney and Mcloud there are no services, and the gas station in Mcloud is not big rig friendly. Mt Shasta is the next stop with easy fuel.
On the plus side -- the road is all good and no uphill grades of any concern. One steep downgrade into Old Station for about a mile or so.
Lots of boondocking opportunities if you want to stop enroute.