Basically, as the title says... is there any way to have user input directly on the report? I know in Adobe PDF documents you can have textboxes that a user can type directly into.
No. An RDL/RDLC is a report.
Comparing an RDL/RDLC to the way Adobe PDF operates is like so:
With AdobeLivecycle Designer you can create a PDF with form elements in it for the user to fill out. Then, when the user is finished and previews/saves the document it generates an actual PDF.
This would be akin to designing a UserControl/Window/Page in a way that it's layout resembles your RDL/RDLC. Then, when the user clicks a "Save/Preview" button on your control it sends the necessary info to the ReportViewer which generates a report.
PDF FORM = UserControl/Window/Page
PDF = RDLC