Help Getting Scheduling Project Started

Hi all, I'm just looking to see what method you would recommend to complete a project involving scheduling home visits. I really just need to know how to start and then I think I can handle it. I need to:

-> Import data from multiple worksheets from one other workbook. There will be about a dozen sheets each containing between a dozen and five hundred lines of data each. I can either separate the data into a dozen new sheets, but would prefer to be able to put it all into one. Alternatively, I could create a dozen new sheets, then another new sheet that compiles all of that data.
-> There are four spots for dates in each row. I need to be able to pull the data from each row if and only if it has been a certain number of days since the last visit.

My current formulas look like this (for now I copied all data into the same workbook, I know how to pull from another workbook with regular formulas, but if there's something special I need to do for this project please let me know):

C3 - =IF(Sheet1!A5="","",IF(Sheet1!E5="",IF(TODAY()>Sheet1!A5+60,TODAY()-Sheet!A5,""),"")) - Displays how many days it has been since our first visit if the number is greater than 60.
D3 - =IF(C3="",IF(AND(Sheet1!F5="",Sheet1!E5<>""),IF(TODAY()>Sheet1!E5+21,TODAY()-Sheet1!E5,""),""),"") - Displays how many days it has been since our second visit if the number is greater than 21.
E3 - =IF(AND(C3="",D3=""),IF(AND(Sheet1!G5="",Sheet1!F5<>""),IF(TODAY()>Sheet1!F5+60,TODAY()-Sheet1!F5,""),""),"") - Displays how many days it has been since our third visit if the number is greater than 60.

B3 - =IF(AND(C3="",D3="",E3=""),"",Sheet1!C5) - Displays the address if any of the three prior formulas are triggered.

My problem is sorting the data in a useful way without ruining the formulas and allowing the sheet to keep itself up to date. Of the five hundred lines of data, only 20-30 should be ready to be put on the schedule and return a positive result for any of the three formulas. The data in the original workbook is just words and numbers put into a spreadsheet, I could convert it to a table or rework it another way if that makes this project smoother. Thanks for any help!