Makes sense. Dang, I thought I had it all figured out, now have to regroup and put the picture frame in
(is the right terminology the "feature strip"?) It should make the transition look better though. Particularly where the wall ends, it will (hopefully) look less like I knocked out 2 walls :D Now I plan to use 3 strips of 2 1/4" board to bridge the gap to the wall, where the vinyl will take over, then do a perpendicular board of the same color to create the frame.
Now I'm kicking myself I routed off the "tongue" of the parallel hardwood floorboard when I put the 5/8 underlayment in, I suppose I could just make it a "groove" now. EDIT Either that or I'll just replace that board entirely and make it part of the (now even thicker) frame since that piece has some damage and the tongue will be on the wrong side for the air nailer.
Which brings me to some hardwood floor questions:
1) When making the transition for the perpendicular boards- what side should have the tongue and which the groove? Or, does it not matter? In other words, should I "tongue" the butt ends of the existing floor? Or groove it? EDIT- after doing some research looks like I should tongue the existing boards, that way the groove of the perpendicular board will be in the right position for the air nailer.
2) At the 90 degree turn in the frame, I can either Mitre 45 degrees it, or stagger it with the pieces interlocking (remember, I'll have 3 strips to create this frame). Any recommendations?
I have found a fairly close, slightly darker match to the flooring that's readily available prefinished at the Home Depot that should make a good frame.