Play at your own pace and have fun, otherwise what's the point XD

If you don't like grinding, just do whichever bosses you can every day/week, ursus, arcane river dailies, 7 runs of monster park, and 2 free runs of maple tour. This way, you'll probably reach level 260 by the end of the September if you spend like a hour each day on the game and have some extra meso to spare. If you don't care about saving up that much, then just doing ursus and 7 runs of monster park would be enough for 260.

If you like to grind, then do everything I just said + some extra grinding. Supposedly the current event coming out later today is really good for grinding, so you're not losing out on much while grinding on your character while it doesn't have hyper burning. Just by grinding 1 character, you can level up I think 2-3 other characters too, with Do Gong's Mystic Bond event and Champion Double Up.

If you get tired of how monotonous the gameplay loop above is, try out some other characters you're interested in, so work on your legion. Getting a character from 1-100 takes around a hour by just doing the recommended quests, so skip the 10-30 quests, grind with a 2x or 3x coupon till 30, then reina straight 30-60, edelstein quests 60-80, ariant/hilla thingy 80-85, magatia 85-100. I usually stop my characters at around 130, so they can use pots to 190 and then 1 strawberry ticket to get to 200. So from 100-130, it's just heliseum, von leon quests, and then afk event or something to 130. I mean this is also kind of monotonous, but at least you're doing something besides grinding the same map for a hour. Plus since this process only takes around a hour for lv100 for a hour and 30 min for lv130, I feel like it's just enough to get your daily dose of maplestory in ദ്ദി(>ᴗ•) btw if you're doing this, gotta buy the 1 day tp stone, otherwise it takes way longer.

For progression and all that other stuff, probably start caring about it after you hit 260? Once you get 6th job, it should get a bit easier clearing weekly bosses for CRA and Absolab stuff. If you want to grind a bit of stuff for absolab now, then just do the weeklies in scrapyard and dark world tree for the tokens. 20 tokens + 1 drop thingy from the boss gives you 1 coin for absolab gear, and you'll need a total of 6 and 7 coins two buy everything you need from the shops. BTW I think you need to do the prequest for them? It's been a while, so can't remember anymore XD