I think the important thing for a 4 year old is to keep learning fun. They learn so much at that age just by spending time with us and participating in daily life. Here's some information on teaching preschool at home that may help you. It has suggested activities for all subjects:
If you want to add in a few workbooks, I really like the Kumon workbooks or the preshool series by Rod and Staff Publishers:
But at this age, she should need very little bookwork. No more than about 30 minutes per day.