There are few hostels between Lisbon and Porto, and those that are are privately owned (and generally amazing). Between Lisbon and Porto, we stayed mostly in '
residenciais' which are like really really good budget hotels...Clean clean clean, some with lovely historic architectural features, some with cafes or restaurants attached (meals are separate). For the pleasure of a bed, fresh clean sheets, pillow, towels, hot shower/bathroom in the room (or maybe not), convenient location, you will pay about 15E. (Oh, it's not a dorm.) If you meet up with someone as you walk, you can share the room. Cost will be about 15E each.
The food in Portugal was delicious, the people so friendly, the scenery wonderful. The cobblestones? Not so much. There is road walking but also diversions (riverside walks, for example) to avoid some of that. There is trail walking. There are walks through woods. There are arrows, there are places you must be vigilant to not miss the arrows!
If you do go to Lisbon, there are many of places to stay and eat. It's a beautiful city--spend some time there. When you want to start walking, find the Cathedral, get your carimbo (stamp)--make sure you have your Credential already if you are starting on a Saturday or Sunday--you won't be sold one at the Cathedral on those days. Once outside of the Cathedral, look at the stairway leading up to the main entrance door...on the lower left of the stairway, you will find your first yellow arrow! (If you can't find it first off, keep looking. It's there!)
If you read
@peregrina2000's 2014 guide on the website the Confraternity of Saint James, (
www.csj.org.uk) you'll get a much better sense of the Camino Portuguese than my ramblings here. It's a really helpful (and invaluable) guide to read before and during your walk.
The Camino Portuguese was far different than the Frances (for me). I loved it. Fewer pilgrims until Porto. Lots of pilgrims after Porto. You'd get the best of both worlds! (Would I do it again? Oh yes, in a heartbeat!)
Buen Camino, Andy!