I was planning to glue it down, as that is the only way I have witnessed it being installed in person (although I saw some alternatives online) and it is how a contractor I know in person recommended.
I've never used floor leveler before so I don't know how well I can do it yet either. I have mixed, poured, and finished concrete a few times before without trouble, though never without supervision.
We might want to see if the handyman who lives next door to us has any skill with it. He has always charged us less than expected when we hired him before.
I stopped by Home Depot this afternoon and asked some employees about the issue.
The guy in the concrete/masonry department recommended just using some ($7) Quickcrete patch to fill the crack and level the surface, but then got really irritated when I started asking questions about how that would effect the flooring installation over it.
Once I finally found someone who works in the Flooring department to help me, he said that is not the right thing to use and that the only product he would ever recommend for the job is
LevelQuick self leveling underlayment. They only sell it in that 50 lb bags, which is much more than I would need.
He described two ways to use it, either mixing it to the consistency of peanut butter to apply and smooth out manually with a trowel or making it thinner than that and pouring it so that it self-levels.
He said he would strongly recommend a floating installation over a moisture barrier (which would cost between $60 and $120, depending on whether I want the basic kind or a premium one that would also insulate and dampen noise) if I were using the sort of click-locking engineering hardwood flooring that they sell, but admitted that he is not very familiar with Shaw's product line and suggested that I call or visit an authorized Shaw distributor for advice before proceeding.
He showed me the right sort of adhesive to use if I do go with a glue down installation (the kind for engineered hardwood costs $94 for 4 gallons, which is not as bad at $168 for the kind used for solid hardwood), and the kind for if I'm told to glue the tongue and grooves together ($9 for 400 lineal feet).
He said that I would definitely need to purchase a transition piece (especially if I do use the floating installation method), but without seeing the site could not say if I'd need a flat transition or a reducer. (I assume the latter.) He described how to install either one. It would be $20 to $38 dollars for a 6ft section, and I'd need to get two of them and cut one to handle the 8ft wide threshold between the den and the linoleum of the adjacent kitchen. They could not get me an exact match, but I took home several free samples of flooring to see which kind seems the closest. (It would probably make more sense to order an 8ft transition in the exact material from Shaw.)
He showed me the hardwood finish quarter rounds too, but I decided to just go ahead and buy the cheaper plain white primed kind.
I also picked up a gallon of white semi-gloss trim paint and a sample size container of satin paint tinted to match what I used to paint the walls of that room 4 years ago. That should be enough for touchups and for a small section of wall I plan to patch after removing an old in-wall electric heater that I think is a fire hazard. (We have not intentionally used that heater in over 20 years, and the last time it was accidentally turned on we smelled smoke. We used to have pet birds whose cages were kept on the window seat above this, so a lot of bird seed fell into the heater.) I was able to salvage some old wood paneling from another Habitat house, which almost matches what is in this room and should be more than enough to fill the 2ftx16in gap that would be left by removing the boards that were cut around the heater.