How about one more buildable thing that gives you money in one way or another (like mine or like something that increases tradeable goods): Pipeweed plantation. The best places in Middle Earth for pipeweed would be Southfarthing, Bree and some areas of Gondor but others could sow them too.
Since I saw a dwarf fan here, I suddenly got an idea: maybe you should make Iron Hills dwarves independent from Blue Mountains dwarves and give them a possibility to convert into Melkor followers under certain circumstances. If I have understood Tolkien Legendarium correct, dwarven factions that live near enemy realms have had great pressure to start following Sauron and some clans have succumbed. I am not sure if any of the Durins Folk are among those who have turned to follow Sauron though...
Would not go hand in hand with lore (which I can only say is in their honour hehe)
Spoiler Alert, click show to read:
But are not evil by nature, and few ever served the Enemy of free will, whatever the tales of Men alleged.
- Appendix F
'Heavy have the hearts of our chieftains been since that night. We needed not the fell voice of the messenger to warn us that his words held both menace and deceit; for we knew already that the power that has re-entered Mordor has not changed, and ever it betrayed us of old.'
- the Dwarves is very aware what and who they are dealing with, words of Glóin, FotR; The Council of Elrond
'I grieved at the fall of Thorin,' said Gandalf; 'and now we hear that Dáin has fallen, fighting in Dale again, even while we fought here. I should call that a heavy loss, if it was not a wonder rather that in his great age he could still wield his axe as mightily as they say that he did, standing over the body of King Brand before the Gate of Erebor until the darkness fell.'
- their king would not bow to Sauron and then the folk would not since that how Dwarves are, Appendix A
Therefore they are stone-hard, stubborn, fast in friendship and in enmity, and they suffer toil and hanger and hurt of body more hardily than all other speaking peoples;
- Silmarillion
And if a king is killed they will go medieval on their enemies Like when the Orc Azog of Moria killed king Thrór (Oakenshield's grandfather) and his son was told:
...and when he had wept and torn his beard he fell silent. Seven days he sat and said no word. Then he stood up and said: 'This cannot be borne!' That was the beginning of the War of the Dwarves and the Orcs, which was long and deadly, and fought for the most part in deep places beneath the earth.
- Appendix A
Following three concern the Dwarves of Dúrin's House, who as far as we know also ruled over the two other western Houses at this time, and their history as foes of the Dark in general (#1) and Sauron during different wars (#2 Last Alliance #3 War of the Elves and Sauron):
Nevertheless since both peoples [Noldor and dwarves] feared and hated Morgoth they made alliance, and had of it great profit;
- Silmarillion
Of the Dwarves few fought upon either side; but the kindred of Durin of Moria fought against Sauron.
- Of the Rings of Power and the Third Age
Elrond had gathered such a few of the Elves of Eregion as had escaped, but he had no force to withstand the onset. He would indeed have been overwhelmed had not Sauron host been attacked in the rear; for Durin sent out a force of Dwarves from Khazad-dûm, and with them came Elves of Lórinand led by Amroth. Elrond was able to extricate himself, but he was forced away northwards, and it was at that time [in the year 1697, according to the Tale of Years] that he established a refuge and stronghold at Imladris (Rivendell). Sauron withdrew the pursuit of Elrond and turned upon the Dwarves and the Elves of Lórinand, whom he drove back; but the Gates of Moria were shut, and he could not enter. Ever afterwards Moria had Sauron's hate, and all Orcs were commanded to harry Dwarves whenever they might.
- UT