I have to say that I often thought that hiring a bike for a section would be a good compromise. The problem here is your backpack. It can make you top-heavy when riding a bike. Probably you would have to send it ahead. I don't know.
In 2007 Adriaan and I started in Roncevalles and arrived as far as Nájera. We then had to return home. Therefore in 2008, we returned to Nájera and continued to Santiago and therefore completed our Camino. However, we thought that we should go for it one more time and in 2009, we returned to Roncevalles and it took us our nearly allotted 6 weeks to walk to Santiago. Last year we were Hospitaleros and then walked from Ourense to Santiago - but it wasn't the same. On this short walk, I didn't get any feeling of the Camino Spirit and arrived in Santiago rather disillusioned. This year, we will return to Roncevalles and, as we have only 33 days to complete the Camino, I already know that we will have to jump on a bus a couple of times. I would prefer taking the bus into and out of both Burgos and Leon, even although the alternate route into Burgos is very pleasant and also the walk out of the city is not too bad either. Adriaan thinks that we should take the bus from Carrillon to Sahagun, thats more or less 100 kms. I personally would prefer my choice. Time and circumstances will tell! Anne