Being able to access the Snowpeak Ruins without obtaining the Reekfish Scent is a very big sequence break. Having early access to the ball & chain also opens up unique strategies in the overworld and in combat.
After Lanayru Twilight is cleared, the ice door blocking access to the Peak Province is no longer there. (This wall can also be bypassed using cutscene diving on a file that has the Master Sword Early while still in the Lanayru Twilight.) However, attempting to ascend Snowpeak without the Reekfish Scent will cause Link to void out in the snow, even if following the Reekfish Scent path.
To prevent the snowstorm from voiding Link out, perform Map Glitch upon entering the Peak Province from Zora's Domain. Howl at the howling stone before digging into the connection cave to remove Map Glitch so that digging doesn't softlock the game.
With a very precise position and good luck, it is possible to superjump off of a wolfos to reach the upper cliff, bypassing the void trigger and allowing access to Snowpeak early without Map glitch.
It is possible to to get to Snowpeak after warping the meteor after Eldin Twilight but before beginning Lanayru Twilight.
This requires Fixed EMS for Barnes’s Bomb Bag and a rupee dive. Once the ice is thawing you need to be on the land on the right side, from here use your bombs on the rocks blocking the path to reveal a blue and yellow rupee which will not despawn and can be used to setup the Rupee Dive. Use the box to push the rupee to the edge of the land, when ready do the Rupee Dive, wait half a second after you can close the textbox then close the text to stop the dive, from here you can swim up towards the Snowpeak Mountain exit, if you start getting carried away by the water current towards in bounds you can use the boots to sink again and control yourself, once behind the ice wall the current can clip you back in bound and allow you to enter Snowpeak Mountain.
It is possible to reach Snowpeak before melting the ice in Zora's Domain, and thus to reach Snowpeak Ruins without ever getting to Kakariko Village. To do this, first activate map glitch to avoid a crush void later on. Then, use the boomerang to grab a keese from the top of the waterfall in outside Zora's Domain, and with an LJA to the out of bounds cliff, navigate with the Keese to a ledge just above the lower tunnel area. Throw the boomerang + keese out so that it will follow Link, then sidehop down left to land in the lower tunnel. Bring the keese up to the rock blocking the shortcut, then perform a Superjump off of it so that Link lands on top of the rock. From here, with a precise position and angle, it is possible to backflip to the right-hand portion of the rock and slide off of it. With two frame-perfect jump attacks, Link will land on a lower portion of the rock, allowing him to move for a moment before slipping off. From here, perform a backflip, and with a good angle, Link will clip out of bounds beside the rock. Equip Iron Boots mid-backflip to land on top of the rock in the out of bounds area. Finally, perform an LJA from on top of the rock to land down in the cave leading to Snowpeak. Because Map Glitch is activated, the loading zone is deactivated, but moving further into the tunnel will set the save location so that savewarping will spawn Link in the tunnel. After reloading the save, it is now possible to enter Snowpeak.