Sledding In One Command (Raw)

/scoreboard objectives add Shift stat.sneakTime
/scoreboard objectives add SledHold dummy
/scoreboard objectives add SledSpeed dummy
/scoreboard objectives add SledMove dummy
/scoreboard players tag @e[type=item] add Planks16 {Item:{id:"minecraft:planks",Count:16b}}
/scoreboard players tag @e[type=item] add Iron4 {Item:{id:"minecraft:iron_ingot",Count:4b}}
execute @e[tag=Planks16] ~ ~ ~ execute @e[r=1,tag=Iron4] ~ ~ ~ /particle snowshovel ~ ~1 ~ 0 0 0 0.1 1000
execute @e[tag=Planks16] ~ ~ ~ execute @e[r=1,tag=Iron4] ~ ~ ~ /summon item ~ ~2 ~ {Item:{id:"minecraft:diamond_hoe",Count:1,Damage:1561s,tag:{display:{Name:"Sled",Lore:["Press shift and look down to enable"]},Unbreakable:1b}}}
execute @e[tag=Planks16] ~ ~ ~ execute @e[r=1,tag=Iron4] ~ ~ ~ /kill @e[r=1,type=item]
/scoreboard players set @a SledHold 2 {SelectedItem:{id:"minecraft:diamond_hoe",tag:{display:{Lore:["Press shift and look down to enable"]}}}}
/scoreboard players remove @a[score_SledHold_min=1] SledHold 1
/execute @a[rx=90,rxm=90,score_SledHold_min=1,score_Shift_min=1] ~ ~ ~ /summon horse ~ ~ ~ {NoAI:1,CustomName:"Sled",CustomNameVisible:1,Tags:["Sled"],SaddleItem:{id:"minecraft:saddle",Count:1b},Variant:0,Tame:1,Attributes:[{Name:generic.maxHealth,Base:100},{Name:generic.movementSpeed,Base:0.01},{Name:horse.jumpStrength,Base:0}],Health:100.0f,PersistenceRequired:1,Silent:1,ActiveEffects:[{Id:14,Amplifier:0,Duration:20000000,ShowParticles:0b}]}
/execute @a[rx=90,rxm=90,score_SledHold_min=1,score_Shift_min=1] ~ ~ ~ /summon minecraft:armor_stand ~ ~ ~ {Marker:1b,Invisible:1b,NoGravity:1b,Tags:[SledStand],ArmorItems:[0:{},1:{},2:{},3:{id:"diamond_hoe",Count:1b,Damage:1561s}]}
/clear @a[rx=90,rxm=90,score_SledHold_min=1,score_Shift_min=1] diamond_hoe 1561 1 {display:{Name:"Sled",Lore:["Press shift and look down to enable"]}}
/execute @e[tag=Sled] ~ ~ ~ /teleport @e[tag=SledStand,r=5,c=1] ~ ~0.5 ~ ~180 ~
/execute @e[tag=Sled] ~ ~ ~ detect ~ ~-0.1 ~ air 0 /scoreboard players add @e[tag=Sled,r=0,c=1] SledSpeed 6
/scoreboard players remove @e[score_SledSpeed_min=1] SledSpeed 2
/entitydata @e[score_SledSpeed_min=25,score_SledSpeed=30] {Attributes:[{Name:generic.movementSpeed,Base:0.1}]}
/entitydata @e[score_SledSpeed_min=55,score_SledSpeed=60] {Attributes:[{Name:generic.movementSpeed,Base:0.2}]}
/entitydata @e[score_SledSpeed_min=75,score_SledSpeed=80] {Attributes:[{Name:generic.movementSpeed,Base:0.3}]}
/entitydata @e[score_SledSpeed_min=100,score_SledSpeed=105] {Attributes:[{Name:generic.movementSpeed,Base:0.5}]}
/scoreboard players set @e[score_SledSpeed_min=110] SledSpeed 110
/entitydata @e[score_SledSpeed=0] {Attributes:[{Name:generic.movementSpeed,Base:0.01}]}
/execute @a[rx=-90,rxm=-90,score_Shift_min=1] ~ ~ ~ execute @e[type=horse,tag=Sled,r=2] ~ ~ ~ /summon item ~ ~2 ~ {Item:{id:"minecraft:diamond_hoe",Count:1,Damage:1561s,tag:{display:{Name:"Sled",Lore:["Press shift and look down to enable"]},Unbreakable:1b}}}
/execute @a[rx=-90,rxm=-90,score_Shift_min=1] ~ ~ ~ execute @e[type=horse,tag=Sled,r=2] ~ ~ ~ /particle snowshovel ~ ~2 ~ 0 0.5 0 0.1 1000
/execute @a[rx=-90,rxm=-90,score_Shift_min=1] ~ ~ ~ tp @e[type=horse,tag=Sled,r=2] ~ ~-500 ~
/execute @a[rx=-90,rxm=-90,score_Shift_min=1] ~ ~ ~ kill @e[type=armor_stand,tag=SledStand,r=2]
/scoreboard players remove @a[score_Shift_min=1] Shift 1