Actually, we dont take the caravan, we stay in a Gasthof at Gamsjaga, which is on the road between St Gilgen and Srobl. However, right next to the village, at an area called Gschwandt is a caravan touring site and adjacent to that at Farchen is another. I have looked at both on our last visit, and at first glance, they are excellent. If you check out
http://www.lindenstrand.at/camping-wolfgangsee-salzkammergut.html
and
https://www.seecamping-primus.at/
Wolfgangsee, although fed from the mountains is extremely warm in high summer, and the water feels tepid rather than cool. A word of caution though, parts of the lake bed are very stoney and soft shoes are necessary.
On the far side of the lake, on the Strobl side of St Wolfgang, there is another touring park that we passed regularly, but I didnt actually check that one out. See
https://www.appesbach.at/en/
and another at
https://www.seeterrassencamping-ried.at/de/
From St Gilgen, the cable car up the Zwolferhorn, and the train up the Schafberg from St Wolfgang are excellent trips, but Dachstein really is the crown jewel.
See
https://www.derdachstein.at/en/dachstein-glacier-world/glacier-experience
Hallstatt is well worth a visit, as are the salt mines, either at Hallstatt or Hallein are a great trip on a damp day, and a day out with a difference, though a bit of a drive is the Austrian Holocaust Museum at the old Mauthausen concentraion camp. I have visited both Dachau and Auschwitz, but for some reason I found Mauthausen affected me the most, possibly because it is more complete than the others.
We have also stayed at Mondsee, famous for the Sound of Music Cathedral, but to be honest, found Mondsee not a patch on Wolfgangsee.
On Schafberg, that is actually Mondsee in the distance, Wolfgangsee is to the left of the mountain.