with the complexity of this form, I would use security assist to have the person first create an account, and login.
this is a very cumbersome form to have on one page, and you will want a way to track the information to the person.
When the person logs in their ID is stored in a session variable.
I would break the form into smaller chunks and have a separate page for each piece of the form, on each page, store the form data to a database table using the insert record behavior, each form will insert to a different table.
each table should have a column to store the users ID session to relate the data being inserted to the user.
on the main users page, have links to each form
the user could use the barn insert page to add multiple barns
or use the home insert page to add multiple homes.