arguably this is the best start with the most loot to grab straight off, could be the start that gives your crew the best launch

PART 1    so from the off, turn SOUTH to Old City, turn right and immediately turn right AGAIN up stairs to a blue floodlit Castle Arena
PART 2    Assess the Arena and note the blue wall button behind you and the centre trapdoor. Now find the big herder straight ahead, see the floor pressure plate? to the right is a LADDER going up to a ledge, further to the right is a group of 4 Mummies, defeat these and the centre trapdoor unlocks.
PART 3    make sure you have a good look around , there are 3 spiders to slay and all 3  should be slain to make the most of this level.
PART 4    Pressing the blue button releases 2 of the 3 spiders by the blue button, you could start the action that way, but a better method would be to place an item onto the floor pressure plate where the Big Herder is
PART 5     dont worry about getting a torch yet, you will have one very soon anyway
PART 6   place an item onto the floor pressure plate where the Big Herder is, the cage where the ladder is UNLOCKS, ascend the ladder to the ledge, now thoroughly explore the ledge
PART 7   at the SE corner of the ledge find a secret cache chamber, select the torch and other items
PART 8   at the mid Northern ledge you find a portcullis gate. through the gate you can see 2 further portcullis gates going back. Each portcullis is unlocked when you slay 1 spider
PART 9   jump down onto the 4 Mummies along from the ladder previously described, see that the the centre trapdoor has unlocked, now LEAVE the level back to where you strated the game. see a magic bridge has energised, cross the bridge to a sack load of artefacts 
PART 10  return to the blue floodlit Castle Arena, return to the ladder up, ensure the ledge is fully explored, jump down onto further foes and slay the lot
PART 11   as each spider is slain return to the mid Northern ledge where you find another portcullis gate has unlocked revealing artefacts that assist your crew
PART 12  when a lot of the foes have been slain and the blue floodlit Castle Arena is looking pretty sparse, press the blue button. this releases 2 of the 3 spiders by the blue button, but now descend the stairs back down to OLD CITY, slay the Crowern Guard and note wooden sliding doors slam shut as you enter a new sector, do not be alarmed! but do be cautious and ready to fight, use strategy to decide where in the new sector you will go, try not to get surrounded but see if there is any loot to be had in the immediate vicinity, you should find crystal shards
PART 13   return to the  blue floodlit Castle Arena, hopefully with the crystal shards (removing the crystal shards unlocks the wooden sliding doors) and now finish off anything left standing
PART 14   once most of the foes have been slain you should find 3 ways to go, 1 >  return to Old City 2 > descend trapdoor 3 > move through 3 "spider" portcullises. each of these routes are strategy decisions, so which do you choose (recommended is no 3)
PART 15   once all 3 spiders have been slain move through 3 "spider" portcullises, drop down to Skeleton Soldier barracks. look for candles high up. head for the candles and find wall cloths with ivy growing over them. move in between the wall cloths into a back room area, ascend the ladderPART 16    slay all the barracks foes and if you see a tiny rat on the floor, note that location, you should come back to this location later for a Brucie Bonus
PART 17   as you slay foes in this sector, gates unlock allowing access to the next region. if you come up against locked gates, retread your exploration of the area in case gates have opened at the other end.
PART 18    at the Eastern end of the sector, a trapdoor and a stairs down will be found. descend the stairs to a ledge and place 1 item into EACH alcove, now return to the location at Part 16 where a tiny rat was seen on the floor
PART 19    now return to the trapdoor seen on the Eastern end of the section, this should now be open but if not ensure all foes are slain OR drop down from the ledge alcoves mentioned at Part 18
PART 20   if dropping through the trapdoor (recommended) yiou find the crew on a smal, platform fighting Mummies , descend from the platform
STAGE 1  you find two sleeping herders. the far gate is locked next to a floor pressure plate 
STAGE 2  awaken 1 herder to tread on the floor pressure plate , this unlocks the gate
STAGE 3  move into the next chamber which you see has four floor pressure plates , get the same herder to tread on each of these floor pressure plates, each time a gate at the far end unlocks 
STAGE 4   as soon as all four gates have unlocked move BACK to the ugguradians den where a Brucie Bonus cache has unlocked for you (optional)
STAGE 5   TIP! be wary of the trapdoor near to the four floor pressure plates, this swiftly moves your party down to the next level, entirely skipping the whole of Oblivion, ok if that is what you want then good result, otherwise keep closing that trapdoor with the adjacent wall button. 
STAGE 6   TIP! if your herder gets wiped out before setting floor pressure plates  then you do have 1 herder left in reserve but ensure he does not die yet
STAGE 7   once the four floor pressure plates have all been set take your crew down the "Crowern" passage where you find 1 more floor pressure plate in the centre of a large hallway , your last herder must tread on that OR you cannot proceed much further in Oblivion. if that happens use the trapdoor mentioned at

Stage 13, or return to the pushblocks and solve the puzzle there. 
STAGE 8  TIP!  once the four floor pressure plates have all been set, you could do some backtracking back to the Ugguardian base to see if there are any bonus caches? if you try that SAVE THE GAME first
STAGE 9  TIP!   once the fifth floor pressure plate as described in Stage 15 is also set - your crew could backtrack to the PushBlocks to see if any bonus caches have unlocked there? 
STAGE 10  TIP!   the first trapdoor that is seen in this Oblivion world doesnt seem like much but it is literally a trap. It will keep opening and your crew will sooner or later fall into it by side stepping or moving back. Either dont do side stepping or moving back OR keep the trapdoor closed by pressing the wall button next to it.
STAGE 11  TIP!  once you have slain most of the creatures, you should see three new chambers to explore. one has a light and a trapdoor and one has stairs down and one has green pointy shoes. each chamber has more going on than it seems. TIP! dont go down the stairs unless you have FINISHED with this level and just want to move on to somewhere else. TIP! the chamber with the light and a trapdoor: the light has a small button, press it and it unlocks the trapdoor adjacent BUT ALSO the dropdown in the green pointy shoes chamber is now OPEN! GO THERE!  
STAGE 12   explore the three new chambers to your satisfaction and either move on to adjacent areas or go back to the Uggardians den/ pushblocks (see TIP above for best strategy) 
STAGE 13   if your crew found the flashing magic bridge then GREAT, your crew can now score big time with bonus items aplently but if you fall, the bonus cache is over!
STAGE 14   either way you can move South to the Ratboss den. this den includes a trapdoor underneath the wooden bridgeway, this leads to the holy Meteor Armour that is prized across the fifedom, just defeat the ratbosses and the trapdoor opens (if your crew survive) however there are several other options from the ratboss den that are almost as good, so some good exploration here may repa dividends.