With the extra equipment, and most importantly, with access to her past research, documentation and schematics, the woman who invented time and universe travel had managed to recharge the tank of her masterpiece in half the time it originally took. It wasn't an exact science, and it would be only the second time it'd be tested, but the genius had been confident enough in her ability to actually bet her daughter's life that it'd work on the first try. And work it did, because she was Bulma fucking Brief.
Four months was long enough for Trunks to return to some of her old routines, with the addition of delivering some of past Bulma's supplies to other survivors. Reconstruction wasn't on the immediate to-do list, not while the looming threat still existed, but a little comfort was necessary to keep the flicker of hope alive in the different undergrounds. As long as each had enough resources and each group was separated enough, the militias more or less kept to themselves, and sometimes even cooperated through trade or the radio, for the time being. Bulma had chosen to remain in the underground floors of her house, instead of moving into larger, more 'communal' places. Too many questions about Trunks and Gohan, otherwise, and she needed to be able to work without interruption. People knew about the Golden warrior who had stalled many times the Cyborgs. They didn't know there were two, let alone their identity.
Some things did change since Trunks' return. Bulma had prepared her daughter mentally for just about anything, trying to keep her hopes about her father low, the importance of her identity being secret except maybe from Goku (until she was born, at least), to manage the potential jealousy and unfairness feelings that would plague her mind while comparing the two eras, but she didn't prepare her for how to deal with missing her mom. It just didn't cross her mind. The kid was independent, forced to mature quickly in their dire circumstances, her mother and Gohan were still her only friends and family. She learnt young to stay reserved, occupy herself and not bother her mother's important work. The woman had no time to be really motherly, so the child bottled up her anger, need and confusion, only releasing it whenever she could manage to convince Gohan to spar with her, to train her. Once she started to understand what the genius was doing, she put great effort into entering her world, helping whenever possible, and it took Gohan's death for Trunks to finally let go of her resentment and understand Bulma's love language: work.
Trunks never mentioned how hard it was being around her past self and not being able to be touchy as usual, and overall acted well adjusted, but the teen's actions still changed enough for her overworked mother to notice. The girl became much more clingy than usual. Sure they were close, but since her return, she would almost follow her to the bathroom. Touch starvation was real. Asking what was wrong never worked; she had Vegeta's blood and intense gaze, and her desperate hold of her when she returned gave her enough answers. The pair had often slept together during the few rare times they napped at the same time, but since her return, when Bulma slept, Trunks laid against her and held her, and when Trunks slept, either she forced her mother to hold her, or just dozed against her back, shoulder or on her lap while she worked. Fighting off a Saiyan's grip was pointless, so Bulma just accepted it. Proper lengthy rest had been lost to both of them for the better part of the decade, so the sleep pattern they both had wasn't affected. Trunks had confided she slept just about the same in the past; sporadic naps. Bulma knew it would take a while once peace was obtained for her child (and herself) to return to healthier routines.
The Senzu sprout grew slowly, and Trunks didn't know what the plant was supposed to be like, but one morning she saw a tiny bean, so she was reassured the wish had worked.
She had to reluctantly promise she wouldn't go after the Cyborgs until at least one bean was fully grown. Bulma resented the plant, in a way, as its maturation meant the teen would rush to battle again. After Gohan's death, Bulma had tried to force her to stay and not face them again, but the hot-blooded kid never listened and the painful days-long bed rests over the past few years hadn't deterred the teenager from trying again. She inherited both her parents' stubbornness. Truth was Trunks hated every confrontation, but she didn't value her own life all that much, at least not more than any other survivor's. And unlike them, she could take a beating and have a decent chance at survival; and if a few muscle tears and broken bones could save people, then Trunks was eager to accept the trade. Prior to her trip to the past, she kept the radio on at all times, and rushed at every possible instance of Cyborg strikes, like Gohan used to. The monsters couldn't be sensed, so evacuation orders were the only way to find out where they were.
Arguably she'd become more cautious since her trip to the past. The first time the cyborgs struck when she was back, she focused on quickly clearing the blocked entrances to the undergrounds and the roads, then provoked the cyborgs playing cat and mouse in the broken buildings. Guerrilla tactics, in a way. She technically didn't break her promise to not go after them, but she came home with a couple of broken ribs. Trunks' body, like Vegeta's and Goku's, had the ability to heal 'superficial' wounds easily, so that test against the killing machines had taken her less than a week of 'taking it easy' to fully recover from.
The Cyborgs' strike schedule was absolutely unpredictable. They'd sometimes spend a couple of years without a peep, then obliterate three towns in a week. They traveled a lot, and sometimes came back to a place they'd destroyed either a few months or a few years prior, just to cause more despair and hopelessness. And they loved the terror that inflicted.
Once the first bean was mature, at least comparing it to the two she'd eaten after sparring with Goku in the past, Trunks kept closer to the radio than usual. Part of her felt guilty to wish they'd actually attack, but part of her also wanted to face them. She even kept it on when her mother cut her hair; it had reached that annoying 'too short to tie, too long to not get in the way' length. Bulma shaved the sides and trimmed short enough so it wouldn't get in her eyes. She was no hairdresser but Trunks didn't care as long as it was functional. She did her daughter a middle part to check for basic symmetry.
The machine had finished charging without any news from the Cyborgs, and Bulma was relieved. Even if her daughter was going to fight in the past, she wouldn't be alone, and the gang had a little under three years to prepare for the menace, surely things would turn out well. And yet, this time's farewells were more worrying for Bulma: she knew she was sending her teenager to war.