This manga is a masterpiece. There isn't any other way of putting it.
Seriously, I don't think any other manga has ever managed the tour de force 'A Room For Two' has successfully executed. We are at 6 volumes and about 5 years into the life of two girls intensely in love, and every development is a positive and uplifting one. No contrived conflicts here: no angst, no spats, no love triangles, no haters, no worries about gayness being wrong or unnatural or whatever, nothing but the simple happiness of loving each other and caring about each other with all their hearts. And it's one of the most exciting reads I've ever had the pleasure to enjoy, with nary a moment that feels tedious or repetitive or lacking in authenticity. Yukiko-sensei must have been blessed at birth by the yuri fairies with the gifts of brilliant storytelling and mastery of narrative pace and virtuosity at character development; there isn't any other explanation for this level of accomplishment. That's what I honestly believe.
You're right, you're absolutely right. It is extraordinary.
Most people tend to assume conflict is the one major literary element without which a narrative structure cannot move forward, and expect to see a whole lot of it in any good story. Writers are often judged by how many points of conflict they include in a tale, how these conflicts are resolved, and how neatly and satisfyingly the closure is tied up. The ancient Greeks already held "agon" (the act of conflict) as the central unit of any plot; and, even today, many contemporary critics believe that conflict is the crucial feature of any literary creation -- or, in other words, that a story simply must have conflict as an indispensable source of tension and drama to hold the interest of the audience.
And, well, to all these people, I guess Yukiko-sensei would reply like this:
haha-ha haha-ha haha-ha ah-haa BLLLLL ah-haha