The trim in your rooms is outstanding. To "tie the rooms together", the one thing I would do is install chair rail the same color as the existing trim. The horizontal lines of chair rail will move the eye around the room and into the next room creating a flow. Chair rail is relatively inexpensive, easy to install and would be wonderful compliment to your existing beautiful trim.

Snan, The bottom oval one in Eskandari's photos would also work in your room (or something like that). The oval shape visually gives height to the room which would work for you as well. I know that shopping around can sometimes be exhausting, but if you were up for the search that would be another option if you're not sure about the round one you have already. I would also look for something that combines the elements of your wallpaper as well as your fireplace (if you are not planning on changing it) in order to bring those together, i.e. try to bring in the color tones of the two.

I agree, I think the kitchen units are quite charming. The tiles date it, the top of the dresser and the piece over the window. Agree, would paint the ceiling a soft chalky white. I know they're becoming a little overdone but metro tiles would suit but handmade ones in a soft white unless you just remove the tiles altogether and have a splashback by the oven. Can you afford to update the floor? The dresser offers good storage space, have you considered either just removing the top half or updating the top so changing the architrave and glass panes? The fire itself looks lovely, do you need the heater in front? I also like the brick but the recesses are dating it. I definitely wouldn't paint the brick, if you were to do anything I think it would need plastering over to cover the niches unless you are able to match the brick. Do you have a better pic of the firep? If you are set on painting the kitchen units, I would look at the really dark greys and inky Blues for the base units, as I think they'd suit the style well, with brass cup handles with a very pale grey for ŵall units. Or if you want the same colour units, look at a mid tone grey.

You can leave the handrail the same distance from the wall as it is now. Leave it connected to the newel post at the top; remove the newel post at the bottom, and add what's called a 'return' to anchor the bottom end to the wall. Then add a couple of brackets going up the stairs. The challenge is that the return should match the profile of the handrail, in order to blend, but check at the home center or a lumber yard/mill to see if you can match it (take measurements/drawings/close-up photos, etc.). As for painting the stairs--be careful with "fun" graphics. The treads and risers need to be clearly defined and regular. For example, a plaid or check that doesn't match the tread and riser exactly at each step is a trip hazard and may not meet building codes. People need to be able to see the treads clearly even without paying attention to them. Walking is an unconscious activity and we need to make it as easy as possible. Confusing patterns are a menace. In NYC, they put new edges on treads on one stairway at one train station that were designed to make them less slippery. However, they also made it more difficult to discern the edge of the tread. In 6 weeks, more than 1,400 people fell down those stairs. Then they redid them. Over 90% of injuries on stairs happen during descent. I highly recommend Bill Bryson's great book 'At Home--A Short History of Private Life'. The NYC anecdote above came from Chapter 14--'The Stairs'. Fascinating and amusing book. My house is 100 years old, so I feel your pain dealing with the changes and additions that happened over time.