Travel to the Fort is a mission in Ratchet & Clank, taking place in Fort Krontos on planet Batalia. Once Ratchet and Clank obtained an infobot from the Brain Scientist on Gaspar in exchange for twenty telepathopus brains, the infobot revealed Chairman Drek's plans to attack Batalia and destroy its Starwatch Defense Cannon, in order to allow safe passage for harvesters to harvest other planets. Ratchet and Clank, along with Cora Veralux, traveled to the planet to defend the cannon.
At the Gadgetron vendor, the Warmonger is available for 28,000 bolts. If you can afford it, this weapon should be purchased right away, as it is invaluable and should take priority over the Plasma Striker (if the latter is not already purchased). If you cannot afford it, it is best to collect and sell more brains on Gaspar until it can be purchased. Use up any raritanium for upgrades and continue on.
From the vendor, there are two paths: one path forward towards the port, and one path to the right up the stairs to a grind rail. Take the path forward, destroying the bladeballs here, to find Cora Veralux battling against a group of warbots, which are best destroyed with the Warmonger or Predator Launcher. To the left of Cora is an Invinco-Lock; this will unlock a room filled with crates and a RYNO holocard. Leave the room, and then wall jump across the walls next to the entrance, taking up to the top of the building, where a gold bolt is found. After this, turn around and use the Helipack to stretch jump across to the next building, on top of which more crates and raritanium can be found. Finally, head back and follow Cora across the bridge.
When you reach Cora, a blarg saucer will destroy the bridge in front of you; use the Helipack to stretch jump across. Several blarg bombthrowers will appear from the snow here and throw bombs, only to jump back in and hide. Wait until they expose themselves again, and fire a weapon such as the Combuster or Predator Launcher to kill them quickly. Alternatively, you can use the Groovitron to disable them when they are exposed and kill them before they can retreat back into the snow. The bridge to the left is inactive, meaning that a bolt crank needs to be activated. Before you do this, look to the hill on the right to find a group of weaker, white rocks; break them with the Fusion Grenade to reveal some crates and raritanium inside. After this, head out and head down the slope to the bolt crank below the bridge, destroy the warbots and bombthrowers here, then turn the crank to extend the bridge.
When you head back up to the bridge, you will spot a cannonball tank crossing over to your position. This tank is a durable enemy that fires cannonballs at you, dealing heavy damage. Dodge the cannonballs and use either the Warmonger or Predator Launcher to destroy it, then progress forward. Before you follow Cora to the left, head up the rocks to the right, then Helipack and jump across a few available platforms to find another gold bolt. Head back across, and follow Cora down the ice slope to the left from the bridge to a larger area with warbots and a bolt crank in the middle. Destroy the warbots and bombthrowers, followed by the reinforcements that arrive. Another tank will arrive; destroy it, and you can use the bolt crank to extend a bridge above you. Take the hill slope up to the bridge and cross it.
After you do so, a cutscene triggers, revealing that the laser turrets in front of Fort Krontos cannot be passed, and as such, another path will need to be taken to get inside. This will commence the mission "Get to the Turret".