It is possible to enter the fort during the dragon attack by following Hadvar in.  This opens an alternate route, and has some interesting alternative options to go with, that I’ll be going over as the guide progresses further through the game.

If you enter the fort alongside Hadvar, you enter the storeroom with him directly.  Once inside, he tells you to hang on a moment while he unties you- he’s not a dimwitted soldier, he knows that on his own he’s liable to get himself killed, especially with Stormcloak soldiers wandering around during the confusion.  Once your hands aren’t bound, he encourages you to pick up some weapons and armor from the area around.

The only weapons currently available are short iron swords, so at least for now you might as well equip two of them, it’ll let you deal out more damage more quickly.  The armor is all light, it lacks gloves- so be on the lookout for a set- and going unmentioned in the room are a few other supplies- mostly bowls, plates, spoons, and baskets.

Once you’re done in the storeroom, Hadvar opens the gate to the central circular room.  He notes that there are Stormcloaks there and suggests giving diplomacy a chance- this is a cue to make sure you’ve got your weapons stowed and not readied.

Unfortunately, it hardly matters- diplomacy rapidly fails, and so whether or not you pull out your arms, you find yourself fighting a trio of Stormcloaks.  It’s not a hard fight, but it’s a bit hectic for your first taste of combat.  If you want to switch to a two-handed weapon, one of the Stormcloaks is wielding a large axe- if you prefer a shield, one of the Stormcloaks has that, and if you want to step up and keep dual-wielding, you can trade one of your iron short swords for the other Stormcloak’s handaxe.  They also all have Fur Gloves, so you can get your hands geared as well while you’re in the room.

Once that’s done, it’s time to move on- as with the Stormcloak side of this encounter, there are a pair of cabbages in a cart just in the hallway, and there are also a few more food supplies in the sacks beside the bench.

Hadvar will lead you down the tunnel a ways before there’s a collapse- and you’re diverted into another storeroom.  Two Stormcloaks will be here, one wielding a mace that will deal better one-handed damage than any weapon you’ve seen so far, and the other wielding a two-handed sword that gives you an option other than the axe.

Hadvar then encourages you to pick the room over for potions- there’s also some wine here, a rabbit and a pheasant, garlic, and a branch of Elf’s Ear.  Towards the end of the room where Hadvar is, you can also get ten apples and some tomatoes, and if you’re thorough, you can find a book on war tactics.  Once you’ve taken whatever you feel you want from the room, walk over to Hadvar and he’ll open the door from there.

A short trip down the corridor leads you to the torture room- Stormcloaks are fighting with a couple of soldiers and the torturer here.  Once the fight is ended, you’re pretty much invited to loot the room.  There’s another book, some skeletons with coin and bonemeal, and a pack on a table with the third book you can find.  This pack holds lockpicks, which you need if you’re going to get into the cell where the rebel mage died- and even if you don’t plan on spellcasting, you want to get in there.  Not only are there some coins and a book of Spark, but the mage’s cloak and hood are extremely valuable and very light- good sale fodder.

The torturer stays where he is, but you bring the other two soldiers with you as you head deeper into the caves where he’s sure there isn’t any exit.

A little ways on there is a room with some railed platforms and bridges- three Stormcloak fighters and an archer wait here, so be ready to fight when you enter.  The archer has a bow and some arrows for you, though Hadvar will give you a bow later if you’re not interested in picking up things to sell.  Another room shortly after contains a number of giant frost spiders- and not only can you collect their venom, but also their eggs from the egg sacs, and some animal tails and a few coin from their webs.

Finally, you have an encounter with a bear- near a cart full of cabbage and wine.  You can sneak past the bear for sneaking experience, or you can shoot it with the bow- better one of those than trying to fight it in melee- the bear is quite strong, though not so tough as to make the fight unwinnable.  If you kill the bear, you can take its pelt and claws, as well.

With that done, you’re ready to head out of the underground and see the world.