FG is quite an experience. As for the instance fight, I'd try for a healer, but you should be able to do it without it. Yeah, I bet for the boss you'd need one. As for the actual dungeon, its routine to see groups of 16-19's fight the stuff at the entrance. Farther in its all around level 17 aggros, which a small group could prolly handle as well. The next large room in it (through third gate) is called the Market, and is mostly level 18 iirc. Grays out at 21. Past that, you really need level 20's, since you start getting (if you're, say, level 20) yellow/orange double undercon group-rated mobs. The dungeon progressively scales up from there, but ifyou get a group from 18-22 (preferably only healers low) you should be able to make it near Market 2 or the slime caves, which would provide some even conning fights.
Oh, and be prepared to die. It will happen in FG. Just remember you can retrieve your shard from FG while you are in the Commonlands (right click the door to FG).
"Jesus saves, Buddha enlightens, Cthulhu thinks you'll make a nice sandwich."
