I did that exactly! Also walked Biarritz to SJPdP to Pamplona to Somport (via Camino Aragon) then on to Lourdes (Arles and Piemonte)! Both routes are lively, have pilgrim support, and with easy to moderate hiking conditions.
For your B to B idea, the path is clearly marked. Accommodations are generally easy to find and many are pilgrim-centric. Some bed difficulty occurs around Markena due to vacationers and the transient surf community, but it’s a minor hassle and not an impassable obstacle.
Transportation to the start and from the end is easy.
What else would you like to know?