A support structure for mounting an accessory assembly to a vehicle having a mounting surface defining a base mount and at least one brace mount includes a base having a connection portion being selectively connectable to the vehicle, and a support portion. The base is connectable to the accessory assembly. The support structure further includes a brace having a mating portion for engaging the support portion, and at least one arm extending from the mating portion toward the connection portion and away from the base when the mating portion engages the support portion. The at least one arm has a proximal end connected to the mating portion, and a distal end being spaced from the connection portion and being selectively engageable to the vehicle. The support structure further includes a lock selectively locking the mating portion to the base.