As mentioned above the route is mostly flat. The coastal route is stunning! Fabulous boardwalks that are easy on the legs and feet, well supplied with places to stop and refresh, interpretive signs in places, water is cold, cold, cold but I swam. There are, of course, some hills but they are not long nor do the rise very sharply. It also depends on how mush hill walking you are used to. The only climb that "got" to me was as I walked out of Redondela on the way to Arcade but it was just short and sharp. Also on the final climb into Santiago seemed to go on a bit, not difficult just long, but then I was feeling a bit of regret that my amazing adventure was nearly over. I had achieved my goal to complete a Camino before my 70th birthday (just). There is an amazing climb north of Mougas that is so interesting that no one should miss it (Camino Portola?) and on into Baiona which is a stunning little town!! I walked from Lisbon through end August through September leaving Porto 16 September. I had six hours of rain one day in Porto where I was resting. I later had three mornings of mist which lent a magical aspect to the start of the day but it cleared within a couple of hours. I stuck to the coastal route as I am a sea sort of person and I was never disappointed. Go for it!