In that case joins and resident loads will be a great help for you. It's had to determine how complex this operation would be - 70 tables into 1?
Try to keep things as simple as they possible can be - dropping every field that was only a temp field or you don't use it at all - I would start from checking the QV Document Analyzer created by Rob Wunderlich
This will definitely help to determine what fields aren't used in your app and what objects are resource heavy in your front end.
My last advice - try to replace some of the joins with ApplyMap() function. If you only need to bring across a small number of columns from one table to the other - do it with ApplyMap() and drop the original tables.
Start from joining/ApplyMap() on the dimension tables and just see if that's matching your expectations. You might also notice that at the end of your work you will decide to stick with a star schema data model rather than one table - if you will search trough Qlik Community you will definitely find some articles about all pros and cons for each solution. Good luck!