On Wutai at least it's not uncommon to see people shouting to form parties to go out and do leves together, especially shortly after reset or during evening in different region's respective time zones. Typically these parties are for R30 leves or R40 leves, but I've seen shouts for R20 leves too.

For an R20 CON, I'd recommend grabbing all the Horizon leves and walking out there. Join behest; it starts every 30min now. Invite some people to do your leves with you. Even if they don't have any or don't have the same ones, you'll get a bonus to SP just for having more people in the party. It shouldn't take very long to get to R23. When you do the R30 leves at Nanawa Mines and Nophica's Wells open up to you. It shouldn't be hard to find people to do those with you if you shout in town. Keep doing leves in parties and you'll steadily be getting ranks, gil, and faction credits. I have nearly 10m gil at the moment, and the majority of it is from doing leves, although nearly half is probably from selling crafted goods. Keep doing main story quests when they become available. The gil rewards for those go up and up. The last one gives 120k!

I hope this helps you get back into the game.