I know next to nothing of the Former Han and can't make the connections your looking for but my intrest is in the civil war that followed the Latter Han's collapse and I know, via ZZTJ, SGZ and works like Rafe De Crespigny's Fire Over Luoyang (which I would recommend for the long term decline of the Latter Han) but I hope information of the Latter Han decline can help till someone can give a wider answer.

In the short term the blame has traditionally been put on the last two really ruling Han Emperors Huan (reigned 144-168) and Ling (168-189) for favoring the eunuchs above the gentry though this has been disputed. The eunuchs are accused of corruption and driving the Empire into the ground with inattentive rulers, signs from heaven (including a series of pandemics), a mass Turban revolt in 184 (though put down by year's end) and "good" gentry figures denied office and the Great Proscription of 169-184 that saw many gentry opponents of the eunuchs exiled or dead . By the time Emperor Ling died in 189, the Han's miliatry grip was declining with Bing and Liang provinces lost to Liang revolts started in 184 and Zhang Yan's Black Mountain Bandits of Taihang had to be bribed into surrender.

Emperor Bian was a child Emperor but the imperial in-laws of the He clan who had maneuvered him into throne would soon be split, Dowager He and her brother He Miao backed the eunuchs, her other brother the General-in-Chief He Jin was persuaded by the gentry to destroy the eunuchs. The likes of Yuan Shao pressed He Jin, persuading him the good name he so desired (the He clan were the first one from outside the usual set of families to have an Empress, the gentry spread rumors about how low their back ground was), to take drastic action but he went for political maneuvers and negotiation to their frustration. After a series of moves, the eunuchs resigned in a bid to spare their lives and He Jin refused to kill them but something unknown leaked from He Jin's camp (I do wonder if Yuan Shao going beyond authority and getting their families in provinces arrested was that leak) and they returned. He Jin then asked his sister to allow the eunuchs to be killed, spies told the eunuchs and on the 22nd of September He Jin was assassinated on way back from meeting his sister. The eunuchs hoped with him dead and with replacing key figures with their own allies, things would return to normal.

The gentry leaders like Yuan Shao and Wang Yun feared for their lives (the eunuchs had not been gentle after the failed 168 coup of Chen Fan and Dou Wu) and hated the eunuchs, the soldiers were livid (He Jin had, unusually for imperial in-laws, sought to win over the troops) and wanted revenge for their popular commander. The He family were not pleased and He Miao went over to the gentry but they promptly killed him for backing the eunuchs. Without imperial support and with the troops siding with the gentry, bloody fighting began, the palace was set on fire, He Jin's body lost and treasures looted, once the troops broke in Yuan Shao and co executed anyone without a beard (non eunuchs quickly learned to expose themselves to survive) and the dead were said to number in their thousands. Some eunuchs like Zhang Rang fled the capital with Emperor Bian and the future Emperor Xian but a posse under Lu Zhi and Min Gong hunted them down, the eunuchs committed suicide by drowning or were killed and the imperial family brought back.

He Jin (who has been castigated for losing and his decisions) had in the build up to put pressure on his sister sought to reinforce his position by calling in the frontier general Dong Zhuo, a very able general but one with a track record of disobedience (this was a bad decision). He was outside the capital when he saw the flames and he advanced into Luoyang during the chaos, in the aftermath he used his soldiers and his wits to get control of the miliatry in the capital, arranging the murder of potential rival Ding Yuan and winning over He troops by faking numbers. With the Dowager lacking supporters thanks to the gentry killing them all and the gentry outwitted, Dong Zhuo seized control.

Dong Zhuo had little political sense and little legitimacy among the gentry but he had the power of soldiers behind him. He deposed Emperor Bian and set up younger brother Emperor Xian, forced the Dowager He to abdicated (then killed her a day later), beginning a series of strict measures to try to restore things. The likes of Yuan Shao, Yuan Shu and Cao Cao fled the capital and use family resources to raise armies, a coalition of governors and powerful figures joined forces, blockading the court from the main farming lands and Yuan Shao (with Han Fu the governor of Ji and technically his boss) tried to get the Governor of You Liu Yu to become Emperor but Liu Yu refused.

With the blockade causing inflation to run rampant and food supplies to be a problem while Yuan Shu's general Sun Jian victorious in the eastern flank, Dong Zhuo withdraw from the capital Luoyang to the old capital Chang'an, taking what treasures he could and burning the capital to the ground. The coalition took the win but didn't pursue having suffered defeats to Dong Zhuo forces, supplies increasingly strained (the Suanzao camp had collapsed due to supply problems) and infighting.

The brutal Dong Zhuo was assassinated by leading minister Wang Yun and bodyguard Lu Bu in 192 but Wang Yun's regime soon fell due to Wang Yun's high-handed manner to Dong Zhuo remnant generals led by Li Jue who feared for their lives. Emperor Xian came of age but remained a puppet until he managed to take advance of the miliatry junta's infighting to escape in 195. However his following was small and his chief generals prone to infighting, they fought a desperate rearguard action till he manged to cross the Yellow River and return to the broken ruins of Luoyang.

Emperor Xian's call to arms to help him was ignored by at least Yuan Shao (advisors Guo Tu and Chunyu Qiong argued Emperor Xian being around would hamper Yuan Shao's power and be a headache) and Lu Bu, possibly several others warlords, but Cao Cao the governor of Yan did come in. With stronger armies and skilled diplomacy, he was able to take charge of the Emperor and took him to Xuchang. Cao Cao used the legitimacy of the Han and ability to assign ranks for diplomatic and political purposes, Emperor Xian would try to break free of his gilded cage via plots from loyalist generals and discontents but plots failed and his pregnant wife Empress Fu was killed.

Cao Cao died in March 220 with two thirds of the land conquered and his eldest son Cao Pi swiftly took control of the kingdom of Wei, spent the rest of year smoothing his way then in the December Emperor Xian abdicated, ending the long reign of the Han. Rival warlord in the west Liu Bei, who had some imperial lineage, claimed Emperor Xian was dead (he wasn't) and, despite some objections, declared himself Emperor of the Han. His state is often called Shu by rivals and Shu-Han by historians to separate from the Han of Emperor Xian. However Liu Bei would soon die and his state failed to make much headway against Wei before Shu's surrender in 263, it generally isn't counted as "Han continued".