We stayed at this site on our first trip overseas with our caravan. We went in July about 3 years ago when Europe was drowning in non-stop rain and this site was blessed with beautiful warm sunshine for the whole of the time we were there. We went right at the beginning of July and left on the day they were closing the Aubisque for the "Tour" to come through. Our last day had low cloud and pour visibility but no rain. We spent all our time in shorts and very light t-shirts even though the site is at several thousand feet in altitude. The only day we wore "longs" was the day we went up the Bigorre. Having said that, if it were to be overcast aroung the site, the altitude would make it very cool.
To do or see...the Bigorre, Gavanie, the market in Argele Gazost, the local tarn about 2km walk from the site, the cheese farm organised walk, the walk and supper at the auberge, Lourds if you can stand crowds (I'm pleased we went but wouldn't go again), and the local walking trail G10 which goes right across the Pyranees.
As far as hookup was concerned, I think we needed our reversing kit which didn't cost very much from our local caravan dealer. If you van is fairly modern, you might have a light on your mains unit which tells you if you need the adapter when you have plugged in and you can just unplug, plug your cable into the adapter, then plug it into the bollard. Its not a big deal once you've done it but we were worried beforehand.
We did the P - St.M overnight ferry then drove to near La Rochelle for overnight. We stayed a little further north on the way back and then spent the last night in a Municipal in St.M which was at the fort right near the centre so we could walk in and find a restaurant for supper. Driving in France is much more relaxed than in the UK. Road users are much more courteous and share the road with other road users. The only busy road we found was the Bordeaux ring road.
Hope you enjoy your trip!
Denise