Knitwear By Joan has just the top and dress pattern for such an occasion, called Knit Girl Summer.
The top and dress have a deep V-neck and ties at the shoulders. The dress has a drawstring waist and a high-low hem.
The patterns are sold as a set and both are available in 10 sizes. They use DK weight yarn.
Check out the pattern on Etsy.
[Photo: Knitwear by Joan.]