Yes, this is quite a silly question considering I've been gamemastering for almost five years now, but one thing that drove me away from (and the same thing that made me return to) D&D 4E was Dungeon Crawling.
We've been using Savage Worlds as our system for a while, but we finally decided to give 4E a second go since we really like the encounters.
Since my group is comprised by two local friends and two foreigners, we use Roll20.net to play our adventures. However I don't have any idea on how to run an actual dungeon crawl using a virtual tabletop.
What I've tried is saving the map image as a file and then using it on the virtual tabletop and using fog of war for vision, however this has two issues:
Playing becomes very boring since it's a mess to constantly move the character minis on the map every time they wish to check something and I constantly have to fiddle with the Fog of War. Some rooms that only have loot feel like a hindrance instead of a reward as we have to laboriously move minis through them while I remove the fog.
The whole map feels like just one big encounter map if we "walk" through it. Instead of specific areas being unique encounters (like "the Torture Chamber is plagued by ghosts" or "this Slime Pit is the home of a Solo Monster") my players start leading the monster into other parts of the map, sometimes making the long encounter way longer. The rooms for encounters lose their focus, and the preparation feels wasted since, well, I designed them for the encounter.
Since the encounters are what brought us back to D&D 4e and dungeoncrawls, these things are really undermining the enjoyment we were hoping for.
So, how do you actually navigate players through a dungeon in an online game?