Migration problems from Excel 93 to Windows 7/ Excel 2010

Hello everyone.

I am currently working on a project that is two-fold in purpose:

1. Maintain an application tool that uses (or operates) on the following platform: Excel 1993, Access 2003 and LotusNotes (a mid 90's version). The application tool was written with VBA 5.
   
2. Redevelop that application tool so that it operates on the following platform: Windows 7, Excel 2010, Access 2010, and Microsoft Outlook 2010. Presumeably I will be coding in VBA 6 or VBA 7.

Now the application relies extensively on writing and reading data from Excel to Access. It also allows user to manipulate the application tool by using a calander ( Calander Control Object 8.0)

I am aware that the calander control object will not work as that object has been removed from the reference library for Office 2010 products. (Am I correct on this ?) So I know this will be an issue.

Furthermore I am aware that there will be connection issues with Excel 2010 and older versions of Access.

I currently have not attempted to simply "open-up" the application tool and see if it runs in the new enviroment. I no that it will not !

I am just looking for some general advice (project management) to go about getting this done properly and promptly. I am working with approximately 6,000 lines of code.

Thanks in advance.