Which track is the best alternative from Sangüesa to Monreal

Hi Gerd,
I've done this stretch a few weeks ago; if you follow the signs (yellow arrows), you will end up walking via Rocaforte.
But if you follow the main road until Liedena, you can walk along an old railroad track through the Foz de Lumbier, and past the Puente del Diablo (at the entrance to the first tunnel). I did this, and it was just amazing, there were dozens of vultures circling above me, I've never seen anything like this before, it somehow felt like Jurassic Park! The downside of this route is that you walk some stretches along a busy road, and the signs are not really clear, especially before Liedena and after Lumbier, where you have to be careful not to miss the path.
I personally would recommend to walk through the Foz de Lumbier, though it's a few kilometres longer than the other route, but the vultures are something you won't see again!
Rolf

I was laying on my back, just amazed by vultures circling above me, until I thought that they might see me in this position and think that I'm their lunch...
When you leave Sanguesa, you have to follow the main road for a few kilometres, past the Camino sign which would bring you to Rocaforte, until you get to a big round roundabout with a petrol station and a motel/restaurant. There you have to turn right into the direction of Liedena, across a bridge, and just after the bridge you will see the signs leading to the left, past an old station and onto the track of an old railway line. There are occassionaly yellow arrows, I think this used to be the original Camino before they created the new route via Rocaforte.
After the Foz de Lumbier, follow the road to Lumbier, across a bridge, and there you need to follow the road out of Lumbier, up a little hill, until the road turns right and a Camino sign points to a track to the left, which you have to follow until a road barrier tells you that this Camino has been diverted because of the construction of a new motorway. There you have to turn left, cross a very busy highway and just on the other side of the road go up a steep hill with some provisional signs (in blue!), until you get back onto the Camino which comes from Rocaforte. An alternative is to follow the highway until Izco/Monreal, but it's really busy with traffic.
This all sounds probably very complicated, but if you are used in reading the camino signs (yellow and other arrows), you will find your way!