I think you are related to Dead Fred!! Maybe a long lost cousin?
The Aragones route is a tough old route.
The climb up to Somport is not particularly difficult though. It has stunning views and at 1640m its a little higher than the 1440m of the Col de Leopoeder on the route Napoleon from St Jean. However, the climb is more gradual than the St Jean route. (I really don't think the Route Napoleon is difficult at all except for the steepness. 13km on a tarred road and 15 on the a path.
St Jean is 163m above sea level.
Borce - the place where most people start the last stage to Somport - is 560m.
To get to Borce you climb gradually from Oloron Ste Marie - about 219m, to Sarrance - 314m.
Unlike the Route Napoleon, which brings you down to Roncesvalles through a Beech forest (largest in Europe) or on the road from Ibaneta, coming down from Somport is spectacularly beautiful - this is real mountain area and the views are breathtaking.
It is mainly from Jaca that the path deteriorates into a rock, gravel, shale, scree trail. If you take it slowly, your old legs will do just fine!
The best place to find a step-by-step description of the route (and all the other Camino routes) is
http://caminodesantiago.consumer.es/eta ... ort-a-jaca
Good luck!!