Hi scottaskinosie,
First off, to backup your Activity table, simply export it using the Import / Export tool. Make sure that you open the exported file with excel and confirm that all of your records are there before continuing.
You will then use the same tool for importing the activity list that you exported from your old account. All the fields should match up already, but you will need to make 1 change. You will be importing the fields RecordID and RecurrenceRecordID from your old account into the fields OldRecordID and OldRecurrenceRecordID into your new account. The reason for this is that Method will generate a new, different RecordID for each of these activities when you import them. You need some way of preserving the old RecordIDs so that you can recreate the recurrence structure.
Once you have these activities imported, you will use a custom action set for re-linking them. You can add a button to your Activity List screen or create a new screen. It doesn’t matter, as you’re going to be looping through the Activity table, not the grid.
Your action set needs to loop through the Activity table for each record that is a Series and contains an OldRecordID. Then each iteration of the loop will insert the new RecordID into the RecurrenceRecordID field for each linked activity. I created this action set myself and have included screen shots below.
I hope that this points you in the right direction, but please don’t hesitate to post back if you have any follow up questions.
-Audisho