Suggestions on Follow Up Notifications

Suggestions on Follow Up Notifications

I would like to be using Zoho Invoicing but would really like to have the ability schedule followup when a customer is inputed.  We use Google Apps and would like to have the follow up notifications go to our Google Apps somehow...

I really do not need the complexity of a full CRM and am trying to avoid going down that road.  Are there any other options or combination of Zoho applications to make this happen easily?

We are a small company now ~5 employees but really want to have the ability to scale this system.

Tim