Give yourself a chance to sink into the expansion missions once you get a job to 99. Many of them can be solo'd at 99, and the story is absolute worth the effort.
And not just the expansion missions. I took a short break after being in serious endgame for several years, and came back as a freelance adventurer with no agenda. Since then I've regained my Medal of Altana, done a bunch of Besieged, finished every single quest in Windurst that doesn't have job requirements I don't meet (except for just one that needs unobtanium AH items), and then switched my nation to Bastok so I can try to solo that mission storyline. Even the Shadow Lord was fun, got rather tight on time when he refused to switch out of physical-immune mode enough. After I finish the missions, my next plan is to do every quest in Bastok, and then on to Sandy, and so on. And watch every cutscene slowly at my own pace instead of rushing because others were waiting. I'm just having a good time and enjoying the world, and have the time to stop what I'm doing and help someone else if they need it.
This is the kind of stuff I did in 2004, and why I fell in love with FFXI in the first place. I'm online less often than I used to be, of course, but every minute I spend in Vana'diel is a pleasure again. I'm even taking chocobos, airships, and ferries just for the fun of getting around the world the old fashioned way. Sometimes I'll turn off /names while travelling because it makes the world more immersive.
And I feel like I've hardly scratched the surface of all the content that I bypassed for endgame.