[zxcvbn]

Originally Posted by Thinlómien

But the Dwarves of the Iron Hills or the Dwarves of the Blue Mountains, they didn't have human neighbours - or did they? No big organised settlements, at least.

How do you know? Tolkien never wrote anything about the Dwarf-mansions of the Blue Mountains and the Iron Hills other than the fact that they existed. It wouldn't be implausible to assume that there were atleast some villages of Northmen near the Iron Hills. And as for the Blue Mtns, they were living right next to the Noldor and Sindar in Lindon.

Originally Posted by Thinlómien

I'm not questioning the fact, but I'd like to look at it myself. Where is that said?

Here.

Ever cool was the friendship between the Naugrim and the Eldar, though much profit they had one of the other; Of the Sindar

And here.

And thus it was that Caranthir's people came upon the Dwarves, who after the onslaught of Morgoth and the coming of the Noldor had ceased their traffic into Beleriand. But though either people loved skill and were eager to learn, no great love was there between them; for the Dwarves were secret and quick to resentment, and Caranthir was haughty and scarce concealed his scorn for the unloveliness of the Naugrim, and his people followed their lord. Nevertheless since both peoples feared and hated Morgoth they made alliance, and had of it great profit; Of the Return of the Noldor

Originally Posted by Thinlómien

I did not mean to say it was too far way for trade, rather that it was too far away for significant regular food supply trade.

Why not? There was a great deal of traffic passing through the old Dwarf-roads, which happened to pass through the Shire.

There he laboured long, and trafficked, and gained such wealth as he could; and his people were increased by many of the wandering Folk of Durin who heard of his dwelling in the west and came to him. Now they had fair halls in the mountains, and store of goods, and their days did not seem so hard,...The Appendices

Originally Posted by Thinlómien

Besides, if there would have been a considerable amount of Dwarven money and/or goods coming to the Shire this way, I think it would have been mentioned somewhere.

The Dwarves did frequently pass through places like the Shire and Bree-land. And as some poster on this same thread said before they occasionally lent their expertise in construction and road-building.

That stage, however, belonged to the early days of the Shire,
and hobbit-building had long since been altered, improved by devices, learned from Dwarves, or discovered by themselves.