Which way?!

Do use www.booking.com to find inexpensive private lodgings. This site has everything from five-star hotels down to private albergues. I walked Port to Santiago in 2015 and used it daily. I use it on ALL my Caminos (four to date). So, I can recommend it highly.

Free Wi-Fi is commonly available in most cafes. It is good form to actually buy something before asking for the password...

We are of the same age. Given your concerns about the coastal weather, yes it can be fickle and fast changing, Consider following this route:

http://www.gronze.com/camino-portugues

Start at stage 15: Porto to Vilarinho, and proceed from there. You should have no problems. This route heads inland from the sea on the first day.

I obtained my first sello / stamp in my credential at the Cathedral at the top of the hill in Porto. I walked to the bottom of the hill to the nearest Metro station to take a train to the edge of the urban sprawl, then walked from there.

I personally find walking in cities and in the industrial estates surrounding them to be dispiriting. But to each his or her own. Camino Rule #1, we do not judge the merit, motivation, worth, or methodology of one another's Camino.

I hope this helps.