We used to be able to sort the track record by parks. Having this feature added back in again might make it simpler for people to spot duplicates and or missing coasters on their track records. This is just something to think about for any future updates to the site you may do, Jeff.
I believe this was asked for in the past. Give it time. If it's already coded, I would think it would come up with the next major site upgrade.
Why hasn't it been done already? Sometimes it would require shutting the site down during the upgrade.
As for spotting duplicates, sort your rides alphabetically. You can easily catch doubles that way.