Just got back from Chelan. What an incredible place in terms of sun and fun. It is *the* place if you like things with motors on the water. For good hearty dinner that isn't too fancy, try The Hungry Belly. Its in a strip mall and doesn't look the part, but it is across the street from the Don Mason Beach and the food is good and simple.
The place has just a few tables, but you can order takeout and meander over to the Park and enjoy dinner by the water.
The kids like the Teriyaki chicken. The portions are giganic, so be ready to take something home. I had the Phad Thai which didn't resemble anything you'd get at an authentic Thai restaurant but was good. The sauce was really heavy and too much, so if you get the Phad Thai ask for the sauce on the side.
Connie had the Caesar salad which was also fresh, but with way too much dressing, so you might want that on the side. The burgers were good and the french fries were really fried. The kids liked them, but I thought they were a little burned rather than just crispy.