Roger,

I did a road only trip of Baja last year with a guy who's been down there a LOT.

We went in through Tijuana and stayed in Encenada on day 1 since we started in L.A. We hugged the coast all the way down.

On day 2 we went to Guerrero Negro. Depending on when you are there, check with the local whale watching company (Laguna Whale Watching Tours) if the whales are in the bay. They are generally there in Feb/Mar. It's amazing as the whales comes right to the boat and hang out and you can pet mom and baby for a long time. Also in Guerrero Negro is Tony's Tacos which is a taco truck that is fabulous. Also Guerrero Nergro has one of the worlds largest salt fields and manufacturing. Lastly it has a large swamp with a hugely diverse number of water fowl. To get there just follow Mex-1 south. You can get fuel in Catavina out of the back of a pickup truck

On day 3 we watched and played with the whales

On day 4 we went cross from the Pacific Ocean to the Sea of Cortez on Mex-1. Along the way we did a fairly easy dirt ride to see some ancient cave paintings. About 25 miles of wide dirt to the Cueva Del Ratón (Cave Paintings). As you approach the Sea of Cortez on Mex-1 you will hit the Cuesta det Infierno (Road to Hell). It's a super windy descent to the ocean. It's awesome! We continued on Mex-1 following the coast to Mulege.

On day 5 we continued south to Loreto but along the way is one of the most beautiful places I've ever been. The beaches of the Bahía Concepción, specifically the Playa Santispac. Loreto is a big tourist city but it's also really cool.

I didn't provide any details of other things to see along the way like missions and good food and places to stay. If you want any of that stuff, let me know. I can also give you my GPX file with tracks and waypoints.

On this trip we turned around at Loreto so I can't help with the next step down to La Paz but its just another 221 miles south on Mex-1.

Additional things to know are:
Mexico requires Mexican vehicle insurance. Sounds like you are renting and that will probably be handled by Motoquest, but just in case. I use BajaBound for mine.
You also need a tourist "visa", called an FMM. If in Mexico for 7 days or less it's free, if more then it's about $24 USD. It's good for up to 180 days if you mark it as such. You can get it online at https://www.inm.gob.mx/fmme/publico/en/solicitud.html. But once you get across the border you need to stop in at the immigration office to pay if needed and get it stamped which is required whether you go with the free or payed one.
I'd also suggest travel insurance to cover you for many possible situations. I use World Normads since they cover you while doing adventurous stuff like riding a big motorcycle.

Hope this helps and please let me know if you need anything!

Joe