in my view, unless you are extremely fit and used to hiking in hot weather, this is really not a wise idea even carrying water. the steepness isn't the problem, it's the fact it's a reasonably challenging uphill walk (well waymarked from the village), and you still have 2km of track to walk around the ruins when you get there - which are lovely, at a height where it is cooler, but to really enjoy it in August, don't walk there and back as well! driving there is pretty but the quality of the vehicle access does vary depending on the season and what they are doing in the forest (felling etc) - this post from Mrs Scorcher