@urbanmamma, I also am sorry for your predicament.
I think my suggestion is a little different from those I have read and takes transport into account.
If you are committed to arrive in Pamplona I suggest:
Stay in Pamplona for a some days doing the things you prefer. As others have said above, much is of it is modern builds but using the old streets. You could consider walking back (about 10 km) and stay a night in the parrochial albergue at Zalbadika and return to Pamplona. Then on to Zicur Menor (less than 10 km) and stay a night. Then transfer to Compostela and do similar half day walks on as many of the various routes that separately come from south east, south, south-west, west and north.
If you are
not committed to Pamplona then I suggest:
Arrive in Compostela and do half day trips exploring the many routes, other than the Frances, that arrive at the Cathedral Church of S James.
This link may give you some ideas. Click on routes in the bottom right to see their names. As well of course finding many more church services. (In October 2017 when I arrived there was a Mass in English at 10h in the largish Chapel of S Andrew, in the ambulatory to the right of the High Altar, but there is much more than just the Cathedral) and the pilgrim community for not just the CF.
Not being a swimmer I did not look at any river seeking swimming hole potential, sorry.
And do not forget to go to Sarria.
Whatever you decide I say, kia ka'ha, kia mā'ia, kia mana'wa'nui (be strong, confident and patient)