I just finalized my deal with a Car Guru's dealer, but I was not able to provide a review, I presume because from beginning to end, the process took a little over a month to finalize, all entirely due to my circumstances. How can I get an opportunity to provide a dealer review again?

I'd suggest that you use the orange "Feedback" button on the right of the screen --or-- The "Contact Us" link at the bottom of the page and send the Car Gurus Admins a message asking them to give you the chance to review the Dealer. Generally, this is auto-emailed within 7 days of contacting a Dealer, but I find it isn't always consistent.