Oregon to La Paz in the dead of winter.
Back when I lived in Oregon and traveled south in the winter, it meant checking the weather channel alot. This is the coldest time of the year and the Siskiyous are often too icy or snowy, so taking the lowest pass in the coast range to get to hwy 101 was often the only option jetting down the 5 to past Cottage Grove and over to the coast and down 101. Plenty of decent camping spots on the coast and I can still remember riding down the coast through intense winter storms with horizonal winter rainstorms. Fun for me, but I like that sort of thing.You will likely see no motorcyclists for the first few hundred miles at that time of year. Heated vest and heated grips and waterproof gear were appreciated. As were hot air hand driers at gas stations. Once you hit the sunshine in central California you will be smiling. Plenty of great camping and riding in California. By the time you get to Mexicali, it will likely still be quite cold at night. The Baja nights are quite cold in Jan-Feb until you get to Baja Sur although it will be 70 degrees and sunny likely by the time you hit La Paz even in the dead of winter. There is plenty of camping in Baja. I checked out RV travel websites when looking. I think Baja Nomads or somesuch. A google search for Baja camping away. I remember nice camping south of Puertocitos on the Sea of Cortez side although I hear that road is mostly paved now, pitch a tent at a nice campground just outside of Mulege , or a bit south at Bahia de Conception,(nice beach camping). Another safe site just south of Catavina, Bay of LA has decent camping although I stayed in a cheap motel last time. I hear costs have risen a lot in the 5 years since I went last, so camping is a cheaper alternative. If I were travelling with a wife I would probably camp near the RV snowbirds or stay in inexpensive motels with showers rather than stealth camping though. Safer methinks.