What you may have to do for the Or limits, is literally look at the gvwr regs. Like here in Wa st, the speed limit is not personal/recreation vs commercial, but ANYONE over 10K gvwr, gcwr or equal can not drive at 70 mph where legal, You must always be no higher than 60 mph! Chain up laws in the mtns are the same in Wa and Or. ANYONE over 10K or towing a trailer, when the chains sign is up for over 10K, you had better have the proper chains on your rig for the number of axels etc. I believe Ca, Id and Mt have similar chain up laws. Speed laws, will not comment on.
Hence why you probably are not finding true answers if you google or equal Or laws from a towing stand point.
Marty