It depends on what type of wood you have and how old it is. In our last house we had 75 year-old birch, and the new planks we added during a kitchen reno always looked a little different (although not enough to really matter...the planks had differentiations even amongst the original wood.) Of course we did refinish the entire floor at the same time... Oak might be easier! In our current house, there are 60 year old red oak floors. They'd been recently refinished (~3 years ago.) We needed to patch in a large section during our kitchen reno, as we removed walls and relocated the kitchen. We simply bought new unfinished red oak (at Home Depot) and a satin poly my DH hoped would match the existing. He expected to have to try a few different finishes and/or stain, but it actually looks identical just as-is. I can tell you----- staining is not the best answer for the long term!! In another part of this house, a previous renovator used WHITE oak, and then stained it to look more like the red oak everywhere else. When we tried to do a screen-and-recoat recently, when adding some new flooring to an adjacent room, we found we were sanding off the stain. So we had to proceed VERY carefully so as not to remove the stain.... otherwise it would have meant a major sanding of ALL the stain, and then re-staining. It was a bummer because there were some scratches and fading that I'd really wanted to fix, but doing so just would have been too big a project. If you want to be able to do easy screen-and-recoats, selectively sanding more where you need to for repairs, DON'T use stain.

When we had our family rooms crown molding put up recently- our crown molding guy took a section of our existing kitchens crown molding with him in order to match. honestly my husband has the better eye when it comes to crown- but in my humble opinion-since your rooms connect- if possible- I’d stick with the same size crown moulding & crown mouldings color to keep the look more consistent & flow nicely.

Unless you're prepared to redo the trusses on the garage it will never match. You can try to deemphasize it by painting the garage door a color very similar or identical to the siding. Remove the asphalt to the right of the garage that goes to the front door and create an attractive stone walkway with landscaping on either side. Paint your front door an interesting contrasting color. I can't see the front door very well - if it's not attractive in its own right, replace it. I couldn't find a picture that perfectly illustrates what I'm talking about, but this is the closest.

If you want to do this, the casing that is "in" a room belongs to that room. Then it is finished in accordance with that room. The part that is in both rooms (parallel to the wall) belongs to one room or the other. You have to decide which room it belongs to. The den in my home has a cased opening to the eat-in kitchen. The den's casework is stained. The kitchen casework is painted. I chose for the shared area to match the den, because the direction that I look most of the time is from the den into the kitchen. With that said, I would choose to leave all of the casing white