There’s a beautiful campsite right next to the “Windsurfing Silvaplana” school – www.campingsilvaplana.ch, but if you want to stay in a hotel or self-catering apartment, the best option is to contact the local tourist office – www.engadin.stmoritz.ch/silvaplana | firstname.lastname@example.org | +41 (0)81 838 6000.
There are many nice restaurants around the lake with typical Swiss food as well as international options. Some of the good Swiss dishes I would recommend you try are the cheese fondue, Raclette and Zurchergeschnetzeltes, a really tasty local stew.
The best airports to fly to are Zurich, Switzerland and Malpensa or Milano, Italy. You can get a train from both to the lake and the journey will take between 3 and 4 hours. If you’re flying with windsurf gear, then you’ll need to rent a car at the airport and driving to the lake will take between 3 and 4 hours.