The problems is the assumption that Alexander II was working towards some form of limited monarchy. In reality it is more likely that he was looking at ways to make the country easier to administer whilst retaining the monarchy and trying to help move Russia forward in terms of its economic development etc.
The reforms that he introduced were never going to satisfy everyone - the old guard resented what they saw as a weakening of the autocracy (and their own grip on power) and growing numbers of liberals saw the reforms as too little too late or a rate of reform that was simply to slow.
If you look at what he had already introduced - local government, education reform, judicial reform, military reform and the abandoment of censoring material before publication - it was all worthwhile but it didn't effectively change the thing that most resented - all power remained technically in the hands of the Lord Emperor.
In 1880 Alexander appointed Loris-Melikov to look at administrative and economic reforms but died before those could move forward - he was not about to grant a constitution but was creating commissions to look at further reforms - we know that was likely that might have included some form of parliamentary body but of course it didn't happen - and if it had you should really imagine a body closer to the limited one granted after the 1905 revolution rather than something closer to the Western European parliaments.
At the heart of the arguement you have two seperate schools of thought fighting for the Emperor's consent - 1) reformers who argued the only way to drag Russia into the modern world and to end anarchist agitation and internal terrorism was reform and on the other hand 2) Those who believed an end to political reform, harsher penalties for agitators and increased monitoring and repression of reformist groups - in effect restating and backing up the autocracy was the only way to save the nation.
Alexander's murder reinforced the view of his already sceptical son and heir that the second approach was the better one - something that was passed on to his son Nicholas (who wasn't really up to the job and like all the Romanov children had been brought up with the attitude the Emperor was always right - moving towards reform for Nicholas was not only a betrayal of his coronation oath but a betrayal of his father).
To move forward you have to keep Alexander II alive long enough to enact some form of further reform and to remain in a loose alliance with Germany and Austria (which might also help avoid Russia committing itself to France and then Britain), you can also try and keep his eldest son alive (though I am sceptical whether he was as pro-reform as some might think), if Alexander II lives into the mid 1890s then Alexander III might have died already (his complaint was in part linked to his drinking) in which case Nicholas II will succeed his pro-reform grandfather.
The last chance for reform might also be Nicholas II dying of typhoid in 1900 succeeded by his youngest brother Michael who was very young and therefore might have been able to move forward in a way that Nicholas just couldn't bring himself to do.
There are other issues - war firstly with Japan and then with Germany and Austria speeded up dissatisfaction and revolution - a different Emperor with a Duma might not have committed themselves to conflict (not defending Serbia would be hard but war with Germany was avoidable if you take away Russia's commitments to France and Britain - Alexander II remained committed to his fellow Emperor's throughout his reign and unlike his son he didn't have a fiercely anti-Prussian wife)