Every dungeon in Ocarina of Time has easy access to its boss room except for the Shadow Temple. In the Deku Tree it's just jumping down the pit and a few rooms later you are there. In Dodongo's Cavern once you have the Giant Dodongo's mouth open it's so close by. In Jabu Jabu I want to say it was either jumping down the hole in the floor to the far left of the door that leads to the 3 way crossroad section and then you'll be there a few tooms later, or it was via that lengthier platform edition to the second room that leads to a new door...? Either way, it's not that far. Forest Temple it's just taking an elevator in the central room. Fire Temple it's accessible right from the first room too. With the Water Temple it's also super easy to get to from the first room. Even the Spirit Temple has an elevator you can activate to get up to the top level fast. Also in Ganon's Castle once the barrier is destroyed it's just going up the spiral staircase.
