For this guide we will be assuming that you are going to make a Mage/Hitter or Mage/Mage combo (This guide is soloable as a Mage or Adventurer easily enough)
Level 1-20 (Friday) (The Unknown) (30 Minutes) Edit
The day we want to start is on a Friday so we can take advantage of The Unknown's hot zone status. Without it being a hot zone, you will likely get around 15-17 levels, as a hot zone that number jumps up to around 20-24. The zone is very simple, have your caster get to Level 2 in Sorcery and then Multi-Blade every fight. For the first 2-3 doors your fighter can have their combat speed set to the 5-second timer and you can focus on just your mage while your fighter loots. Behind the 3-4 doors you will run into guys who survive your MB, that's fine, guard the first round and then thwack the second. This dungeon should take you around 20-30 minutes to complete.
Caster Skill Focus: 2 Sorcery / 5 Meditation Fighter Skill Focus: Weapon
Level 21-200 (Friday) (Festering Hate Pool) (4+ Hours) Edit
We know how this starts, the bat fight. The place where this guide differs is that there are actually three bat fights that are in easy access. I strongly suggest taking out the first two (the one with three and the one with 8). Especially for the first few levels in here since until Med/Sorc are GMed you may not kill all of the bats in the first turn, the group gives pretty good XP and will help. After a while you can skip the 3-bat fight since it will only give you around 2k xp per fight (still a good deal). Run the bat fight until around L80 and then you may begin the circuit of FHP. The circuit is simple and should take about 5-10 minutes per run at max speed (Locations with a * mean there's a fight, avoid the Furies):
Bat Fight: Sarcophagus, South, Reset
Leveling Run: Lever - North* - East* - North - Door - South - Lever - East - East* - West - West - North - Second lever from the right - South - South - West - South* - West* - Lever - Activate Both Buttons - Door - Exit - Reset
Caster Skill Focus: GM All Spellcasting / Acrobatics / Shield Fighter Skill Focus: Weapon / 3 Sorcery / Acrobatics / Shield (for SnB) / Thaumaturgy / Necromancy
Level 175-300 (Saturday) (Forgotten Dungeon) Edit
The Forgotten Dungeon is pretty interesting because the NPCs are random each time you go through. I recommend going as far as you can each time before resetting. You only need one cell-door key for all of the rooms except the one that leads to the boss. The walkthrough I give below is designed as a direct path to the boss assuming you have the key. All of the rooms except for a few have fights, use your best judgement on which fights you engage in. As a fun tip, you can loot the key from the bones without having to fight the NPCs in the room. (Note, Invisibility does NOT work in this dungeon)
South - West - North - North - North - East - East - Door - East - East - South - South - East - East - East - East - Door - Trap Door - East - East - (Bones for Key) - West - West - Door - S. Door - West - West - West - North - North - North - East - Unlock Door - Trap Door - East - East - South - East - Door - East - East - Door - East - East - Door - West - Reset
Level 200-400 (Sunday) (Ascetos Deep Desert) (4+ Hours or Skip) Edit
Sunday is the day of rest and you don't have to go here if you don't want to… but if you do want to, there is a LOT of XP to have here, especially if you can maintain a neutral alliance (which is tricky). Snake Fights and Kilrog fights are very easy here and should net you several levels with little risk. If you feel fancy, try taking on some of the Knights, if you get the feel for it you should be able to fly through the levels very quickly here.
A second option is to go farm/buy a few Heroic Imp Haven keys. Great XP and quick runs (about 15-20 minutes or so). It's a good spot to run through levels if you don't want to hunt overland.
Level 300+ (Monday) (Greater Hives) (4+ Hours or Skip) Edit
Honestly, I hate the Greater Hives. There used to be a great trick here, but after the Mist changes I haven't spent any time in here. Go in, do the first fight and repeat. Honestly, Sunday/Monday are weekends for me for Hot Zones. You can also hit Ascetos Desert or the Heroic Snake Pit, but they are paltry in comparison to the other stuff you've done.
Level 200+ (Tuesday) (Fuloran's Abode) (4+ Hours) Edit
At this point, you can easily handle Fuloran. Don't bother. We're not here for anything but XP and all we need is that first fight. It should take you around 5 rounds to clean the baddies out to get around 3-4k XP and Fuloran only gives out around 2-3k XP for a 10-round fight (there is a chance to get gear here, but it's low enough that I don't bother). The only reason to clear out Fuloran is to get the key for Heroic Fuloran… but you can just buy those on trade channel for about 10k each. Enter the Dungeon, go east, fight, repeat. This is a mindless dungeon similar to that FHP Bat Fight. In one hour, running non-stop, I scored about 30 levels with this fight.
Level 400+ (Wednesday) (Heroic Forgotten Dungeon) / (Anvil) (4+ Hours) Edit
Remember all of those Heroic keys you got running the Forgotten Dungeon? Time to burn through 'em. You know the path, the fights have changed. Good luck!
Alternately, you can run the Anvil. There are a few fights in here that are pretty easy to handle… I personally do not know them because I never really bothered with the Anvil (this will likely be updated once I learn the route).
Level 400+ (Thursday) (Heroic Barracks) (4+ Hours) Edit
You're going to go evil in here, not much you can do about that. This is a fairly straightforward dungeon with one big curse. LOTS of Fairy Queens. An Amulet of Free Will is very useful here. Your only other option on Thursday at this level is to run through Heroic The Foundry… but that's a bit rough.
Level 200+ (Friday) (Heroic Fuloran's Abode / Heroic Tulor's Cavern / Undead Stronghold) Edit
Fridays are kind of strange. Lowest level I recommend is around 200 for any of these dungeons (USH is closer to 100). You have three options today and the last one seems strange. Heroic Fufu, Heroic Tulor, or USH. Fufu is the first fight rinse repeat. Tulor is the spiral to the chest (don't fight Tulor), and the final is USH. I strangely recommend USH, though. Good drop rates and the fights aren't too hard. You also will get some of your own H-USH keys to save some money, and even at higher levels the XP here is still alright. I usually get 3-5 levels each run that takes me around 10-15 minutes with little to no risk. I will give the route to the key below, but exploration will lead to rare drops.
South - Sarcophagus - East - South - South - West - South - South - South - East - East - South - South - West - South - South - West - South - South - East - South - East - East - South - South - East - South - Sarcophagus - South
Level 400+ (Saturday) Heroic Undead Stronghold) Edit
Today is a BIT different than yesterday. Today you are here to clean house. I recommend almost all of the fights (anything with more than one wasp is dangerous). AoFW is highly recommended here and your goal should be to kill FQ and Furies first wherever possible. One run of HUSH netted me around 12 Levels around 600 and took me roughly 40 minutes. My caster did die a few times here so DMP / Endurance is also very useful.