We are on a roll with our summer workbooks. The boys are doing the Summer Bridge books (about $11 each on Amazon). It's just 2 pages a day so they do try to sneak in extra. It did prompt them to enter their goals for the month and a suggested reading list which we will utilize.
Daisy is doing a Kumon Let's Color book ($6 on Amazon). She is just doing 1 coloring a day.
We have been doing this either with snack time or after lunch. Haven't quite fine tuned my schedule yet. After workbook time we have reading time when we work on our library summer reading logs.