How would does vbulletin determine what is a hot thread, and how would I be able to query that because I've been googling, and nothing is showing up.
I would like to be able to have this on a standalone page in a different directory, and access the mysql database in order to draw like 5 recent hot threads.
The Hot Thread threshold can be configured in your vBulletin settings. Set the minimum thread views for the Hot Thread classification.
Try querying based on the number of thread views. Instead of accessing the mysql database for the 5 recent hot threads, go for the 5 latest threads with greater than X views.