I personally never did any quests for adena. I don't think there are many that are worth it. I got into a clan and the guys gave me D+C. Sadly, if you don't know how to make adena in such a raw chronicle as classic without the use of spoiler/crafter ( I still don't know how to make adena without a dwarf to get those crucial item upgrades at 20 and 40 lvl without having to have a somewhat high level dwarf) chances are pretty low you'll have C grade at 40 level. Don't let that discourage you though, plenty of good folks in the server. Try joining Discord and asking for a clan/cp that would recruit and gear you up till C at least, but I imagine most of them will require you to level up a hero that they need.
If you want to do this solo your best bet is to somehow get top D bow or Gastraphetes and start joining RB parties/making them (People here bow the RB while the tank kites it, no matter of your class, up to 55 lvl perhaps. So if you have a decent bow you shouldn't have a problem getting into RB parties from 20-50 lvl). The raid bosses would drop full items and Runes, which you can sell after and get whatever you need. Of course, if you don't want to go through all the #poorlife struggles, a little bird told me there are sites who provide financially struggling in-game customers with adenial support in exchange of tangible,real-life legal tender *wink wink* .
A little general info:
Here is the thing - the characters who have distinguished AOE skills will easily get into AOE parties and AOE means quick leveling, drops and adena. These being mages, pole users, Gladiators, Tyrants, Destroyers, Elemental Summoner (for the MP regeneration buff from the summon. Warlock sometimes gets into fighter parties or AOE, but due to the rarity of the class the trend is not yet established), Swordsingers (very useful in AOE, because of Song of Wind, which buffs the other puller, and also pulls on his own so you get double trains.), Bladedancers (mostly used in mage AOE/CP or generally in end-game AOE spots, often chosen as a puller as well, but sws and tank will be prioritised). Then there are the pure supports such as EE/SE who are always needed. Being a Warcryer will get you into parties, if you choose to go OL though you'll have some trouble finding groups in the random section of the population, sadly.
Single-target classes - Archers, daggers etc., you get the point. You will get easier in random RB parties, you will have trouble finding buffer for duo. If you want to make a box for a buffer that pleasure will cost you 5 euros per month or 120 COL (not sure about the COL, never bought Premium Account). As a single-target hero, your faith is to have a constant aide on your side, so to keep up you will NEED a support with you. So the best thing to do if you're not leveling a personal buffer is to find a clan/cp asap. Although very hard to level, single-target classes can be extremely useful in PVP or situations from different nature. I am saying hard to level, but if you have a buffer with you , you can constantly PVE without pausing, while gathering people for AOE is time consuming, not to mention people leave at random times and you need to find replacement in order for the party to resume, hence the need of CP/clan. So overall you can level even faster than an AOE focused person, but the downside is you're going to spend days and days soloing, something I avoid completely because it kills all the fun.
Some people make AOE heroes and level fast to 70+ then pay 20 euros to class change. If you go for this option make sure you consult the class change guide in the forums.
Tank - the only way to level fast is doing trains or RB. As a tank, you will get snatched as soon as you log in, whether it is AOE or any party, alas tank is tank, and at least for me its painfully boring. The nature of the chronicle is such that AOE and RB are highly preferred, which means you'll be making a billion clicks per day running around kiting and collecting mobs. I don't want to sound like AOE is your only option, you can always single target. I have a friend tank who AOE-d like 20 times and he is 74 now, he preferred to gather a good melee party and grind in LOA. The good thing is your CC and debuffs land with almost 100% probability so at least in pvp you will feel a sense of contribution. Overall tanks can be flexible and all-round you will not experience that moment of being stuck without anything to do. SK soloes well, and so does DA because of hex/panther.
Gladiator - Classic's Sonic Blaster has a stun which completely changed the hero. Very well-rounded hero, good for single-target hunt and AOE due to his high physical damage output. My main is Gladiator and I AOE-ed my way to 70 level, and still AOE-ing. The AOE zones being -> Abandoned Camp from 22-30, Partisan's Hideout 30-34, Alligators island 34-40/1/2, then you need some level to get to Enchanted Valley parties, like 48-49. After that you go Ancient Battlegrounds. The mobs there are conveniently scattered by level so you can start at 55 and level up to 74 if you want, but most folk opt for LOA trains after 68~ (keep in mind you can do ABG parties with randoms, but in LOA you'll need a specific party set-up for things to go smoothly.) Gladiators fair extremely well in 1vs1 situations against fighters given his Lionheart and Dual Weapon Defence, so classes like archers are food. Mages aside from Necro should not be a problem as well (necro has fear, the nemesis of all fighters), in that graph . The only classes a Gladiator can lose to 1vs1 if equally geared (by my personal experience) are DA,SK, Destroyer, Paladin, OL/WC .Bare in mind the above classes are unwinnable with Lionheart, except maybe for the OL/WC, if they are good they will use Soulguard and basically have the p.def of a tank. If you have no Lionheart on, your life can get very difficult as you'll be CC-ed af (at that point you lose vs dwarves ez).
Tyrant - same story as Gladiator but without the Lionheart and ranged stun, so a fair 1vs1 would end 99/100 times a gladi win. Tyrant makes salad out of mobs, gets picked up in AOE as much as a Gladiator( which means without problem). Insane PVP damage output though. Although Tyrant doesn't have that crucial range CC like the newly implemented ranged stun from Gladi or Warlord, he hits like a truck and moves faster than you can target him which is quite useful in mass PVP. The juiciest crit on skill I have seen here was done from a Tyrant to a Mage, both same level (74+) where he Doomed Punched the poor fellow for 9k, effectively sending him to Talking Island or whatever place crushed souls go to. Overall good choice in terms of pvp/pve equilibrium.
Destroyer - never played Destro in a low server, speaking from observation here. Guts and Frenzy are crazy nerfed, you get like 400-500 bonus p.atk from Frenzy, but you get other bonuses like speed, atk. speed etc. That topped with Rage and Zealot can make you move faster than a SWS on a training program for the annual free-run Olympic games. He also has an AOE skill for dual-hand sword, of course you can use the old spear set-up as well. Whether you go for Blunt or 2Handed in pvp you should be fine, just make sure you carry some blunt for stuns.
If you want to land a CP or a good clan go for supports. For example, the server right now has literally 5 high level Bishops afaik. Supports such as OL/SWS/BD/SE/EE/Bishop are always needed and people will fight for an active such to be on their clan. Fuck, if you level fast and go Bishop my clan will gear you up no problem.
Hope this helps, If you have any more questions - shoot, I'll try to answer them as objectively as possible.