That sounds like a blast! We did the quick and not quite as cheap version at Gatlienburg, TN. DH and I took a late honeymoon (Like 5 years late lol) and when we were walking around there was a store set up for it. You bought whatever size bucket of dirt you wanted/could afford and sat on a bench by the trough that had water streaming through it and just shovel full in screen sift keep what's left repeat. I loved it, DH did it cuz I was so excited, when we finished he stated we just spent 30 bucks on a bucket of dirt and got to keep rocks *shakes head*
Hahaha well one of those rocks was a decent size Ruby, there were also some keepable size emeralds and some smokey mountain quarts. Not to mention the prettys that were worth less but just as pretty.