I had an account that I hadn't logged in for 5 years and my characters were still on there. If you are definitely sure there should be characters on the account, then you could make a support 'ticket' with SOE and they'll help you out.
Although either way, starting a new character is often nice to do anyway. Because it teaches you how to play again, and the lower levels are kinda fun anyway. For me at least.
yeah Vanguard has done a great job with providing content for every type of group / solo style you wish to play.
I almost forgot about the fact how nice the game divides mobs into 5 types.
1 dot = almost sure ohk =P some mob pets and stuff
2 dot = standard mob for solo, this seams to be the most spreaded type
3 dot = harder mob for two or three players
4 dot = full groups
5 dot = Raid mobs?
While its true that you can solo with every class, I remember I could solo 4 dot mobs with my cleric. It took a fucking lifetime to kill the mob, but he could do it. My ranger bud couldn,t, i had to help him.
So it was sometimes useful and challeging to solo group quests as a cleric.
edit: I think some mobs have even 6 dots as far as i remember, but rare and only bosses
Yeah 6 dots are the top, you get them in dungeons and raids. I can actually solo 6 dots sometimes with my Dread Knight, but again, it's not really worth it because it takes ages and it's dangerous. In EQ, if you had a strong solo class like a Necro or something, then it was worth trying to solo the Arch Mage or whatever because you could maybe get yourself an item worth 3000 plat or so. Vanguard just doesn't work like that. There are very few items worth a lot of money, and most of them are crafted or not soloable anyway (eg: Finch items from the drop boxes).
So really it's best to just play whatever class you like, and solo whatever you can without making life hard for yourself. If something is too hard, just find a group and you will blast through it fast and it will be far better xp, and far more fun.
The dots system works kind of like this:
1 DOT - very easy, usually dies in a few seconds
2 DOT - standard soloable mob, usually quite easy to kill unless it's higher level than you. Any class should be able to solo these mobs.
3 DOT - Many classes can solo these, some can't. Groups should be able to kill them in a few seconds.
4 DOT - the standard group mob, most dungeons are full of 4 dot mobs everywhere. Some classes can solo these, but they are a longer and harder fight for anyone. Groups should be able to kill them quite easily, if it's alone.
5 DOT - the stronger group mob, most dungeon nameds will be 5 dots. It's not MUCH harder than the 4 dot, but they are still pretty tough. Again, some classes can solo these but it would take a long time and it would be dangerous. Groups should be able to handle them just fine though, if it's alone.
6 DOT - the big bad boss of dungeons, and raid mobs. One or two classes might be able to solo these, in some cases, but it's an extremely hard fight and takes very long to kill. Groups should be able to handle it, but you need to try to get it alone. Some of them have companions/pets that you can't separate, but you need to get rid of any roamers first. If it's a 6 dot in a dungeon, it's basically guaranteed to have pretty nice loot.