No. Recruit Ho-oh to gain access to Western Cave. It's Mewtwo's place.
After you have cleared Pitfall Valley and Stormy Sea, recruit 3 legendary birds, talk to Alakazam then go to the bird's Friend Area. You will be granted access to Silver Trench.
Recruit Lugia to unlock Meteor Cave.
There are numerous events here, but if you cleared Stormy Sea and Pitfall Valley, have all Friend Areas which can be bought/access by doing mission, most dungeons will be unlocked for you.
EDIT: After looking at your post in the other topic, I gonna add something here:
Mew can be found in Buried Relic from 36-98 BF when you keep Music Box in your Toolbox, and if it does appear, once every floor. It will be one of the Pokemon that is on the floor right after the text telling which floor you are on disappear. It can also appear in Monster House. Therefore, the best way to track it down is using X-Ray Specs, defeat all Pokemon that is on the floor right after you enter (not the one that appears as you walk) and keep an eye on the log on the bottom of the screen. If "Mew used Tranform" appears, then there it is.
Celebi is the hardest Pokemon to get to. It's on 99F of Purity Forest, which is the dungeon where you can't bring item, partner, money, temporarily back to Lv1. The best Pokemon for that dungeon is Alakazam*, Mew, Charizard.
« Last edited by nhahtdh on Nov 24th 2008 »