Fans are absolutely loving the new TNG favorites? After all, Picard already did a whole big, nostalgic thing about Data. His other crew on TNG were pretty important to him, too. However, fans don't know too much about where they've been. (Other than the fact Picard doesn't want to bother them or risk their lives on a new, dangerous mission).
Even though everyone knows Geordi would do anything for Data's daughters in an instant. With an episode involving Riker and Troi, let's speculate what the TNG cast of characters are up to now. Theories are something Trekkies are great at.
William Riker and Deanna Troi
Fans have already seen that Riker and Troi will show back up in Picard's life from trailers and clips. Last Trekkies saw of the pair, they had just married and finally confirmed their very inevitable endgame romance. The pair just understood each other way too well and were so ive and loving.
Decades after TNG, Will and Deanna seemed to have settled down to a quiet life on some planet. While fans don't know how they ended up there, it's safe to assume they settled down/retired after a life of adventure. Also, it'd be wild to think the pair don't have a kid or two. After all, any future fantasy either of them had always included a child.
Wesley Crusher
An enigma of the old crew, Wesley was a rising Starfleet star who decided he didn't want that life anymore. Instead, he went traveling to who knows where with the famed mysterious traveler.
While it's unlikely Wes would show back up after that kind of send-off, fans can still speculate what he was up to during all that time. For one, he probably traveled the galaxy's farthest reaches, truly where no man has gone before. He's probably learned more than anyone has ever learned in such a short time period (relatively). However, Wes was always close to his mom and as she aged, he might've come home to help care for her.
Geordi La Forge
Throughout the series, Geordi was just a seriously nice guy with a great mind. After TNG though, he didn't just lose his family. When Data sacrificed himself, Geordi lost his best friend.
While Geordi probably climbed the ranks and, like many alternate timelines became a captain, he never really recovered from losing Data. By Picard, Geordi has probably lived a full life as a captain, throwing himself into his work and whatever relationships, marriage, children, etc. he might have had. However, he never has dealt with the android-sized hole in his life and it haunts him.
Q
If fans are being realistic, it would make sense that Q would stalk Picard to the end of his days. Everyone knows that Q is at least obsessed with Picard, if not in love with him.
However, since Picard hasn't mentioned him at all, let's just assume Q has been a little preoccupied raising his delinquent son for a few decades. When Q had the time, though? He totally would go pester Picard. At the very least the guy's been keeping an eye on his favorite captain. Seeing Q show up in Picard would be a dream, but at the very least everyone knows he's totally been peeking in every so often.
Worf
Considering all the trauma Worf has gone through over the years, it's a miracle the guy has never given up on honor and Starfleet. A traditionalist Klingon through and through, over the past couple decades Worf would've devoted himself to those ideals. And for the love of all things hopeful, fans have to pray the guy at least got to be captain of something.
Trekkies also have to hope that Worf has spent some of his time repairing his damaged relationship with Alexander. After losing two different women he deeply loved and surviving a galaxy-threatening war, he had to want to be close with the only family he had left. Also, no one would mind if Worf found romantic happiness, after all this time.
Reginald Barclay
When fans last saw Reg Barclay, he was a lead scientist at Starfleet and was instrumental in helping get Voyager closer to home. Although he never stopped being a socially awkward goof, his talents never were overshadowed by his anxieties. His close relationship with Deanna was always heartwarming.
During the time of Picard, Trekkies probably couldn't see Reg anywhere else but in some lab, thinking up something genius and life-changing. Ideally, probably involving holograms. After the fall of the synthetics, it wouldn't be surprising if Starfleet chose to rely more on holograms instead.
Miles O'Brien
DS9 as a show wasn't the kindest to O'Brien. However, he did get his own, important role on a vital Starfleet station. Whether he stayed on DS9 or moved closer back to Earth or gave Keiko a turn to explore her botany career, it is sure that Miles stayed a family man. His wife and two children meant everything to him, and he'd always choose a life that meant he could stay close to them. Especially after all the chaos of DS9 and the Dominion War.
During Picard's time, his children might even be in Starfleet or pursuing their own, different careers.
Ro Laren
Ro Laren disappeared after her time on TNG, but fans can be sure she participated in the Dominion War to protect her home from invasion. A lot of her rage and personal issues stemmed from the fact her people were treated so poorly for so long.
While fans really liked Ensign Ro, she probably will never show up again unless Picard deliberately swings by Bajor. Considering how much she cared about her people, she'd probably end up there the older she got, caring for the Bajoran reformation. The Cardassian occupation left a lot of deep, festering wounds and she'd want to help. However, would she and Major Kira ever run into one another? That's a much more likely scenario.
Beverly Crusher
Of all the old TNG characters, Beverly Crusher could be anywhere. She had deep connections to her family roots, so she could be back with them. However, she also cared very much about medicine, so she could be serving as a ship doctor or somewhere at Starfleet Academy. Also, she could even be somewhere wilder in space, with her uniquely-traveling son Wesley.
While Dr. Crusher always was a good person with a good heart, space wasn't her calling like many other people. The people that she loved were. She enjoyed the Enterprise because her friends, old and new, were all there and she could care for them. With everyone scattered, she'd probably find new purpose caring for other loved ones.
Guinan
Fans are already spoiled a bit, knowing that Patrick Stewart invited Whoopi Goldberg to reprise her role as Guinan in Picard season 2. So, at the very least, Trekkies will see the mysterious, wise, and headstrong character again. But what would Guinan have been up to the past couple of decades? And especially where?
Well, fans already know that her species were scattered to the wind after the Borg assimilated them, deep in the Delta Quadrant. After all this time, it's safe to assume Guinan is still traveling without Picard. Either to look for her people or see the sights, fans won't know until season 2 comes.