1 property needs to be one record in a Property table. You can keep all information about all of your properties in one FM file. The knowledge base has articles on how to create relational databases. I recommend you take a look. Below is a basic outline of what you want to do
Create a Property table with a primary key filed, _kp_property, and any other fields you need. Set _kp_property to auto enter a serial number (or a calculation, whichever) so that every property has a different key. Create a Child Room table, with two key fields, a primary key that will hold a unique value for each record in the table and a foreign key (_kf_property) that tells you which property record the child room record relates to. Connect the two tables using Propety:_kp_property = Child Room: _kf_property. You are probably going to need to create a similar relationship between Child Room and children in the room. Note that you mite need to use what is called a "line item" table to connect your records depending on if you have 1 to 1, 1 to many or many to many relationships.
Hope this helps to get you started
"I have built in hundreds of dummy records as well to populate conditional value lists."
That can really complicate your reporting and isn't usually necessary to get conditional value lists to work in a solution.
You've described exactly how I have my solution set up at the moment. Perhaps my description made things sound more complicated than they actually are.
The inventory is completed on FM Go.
Once completed, a PDF of that property needs to be created and sent via email, rather than storing all property records within that .fp7, I'd rather a .fp7 was created with that property's PK_Property_ID and then the file is wiped clear again.
Maybe that makes more sense?