How many people will she typically need to seat in the space?

What is the feel that she wants in the space?

Will she be refinishing the floor in the same color, perhaps adding a rug, or will she be changing the flooring?

Does she have plans about the colors in the space - will the walls be painted or left white?

I could see an L-shaped sectional with one leg on the wall to the right, the other facing the fireplace. A sofa table or cabinet (dresser) behind the side facing the fireplace, with a lamp or lamps for lighting on the table. An end table at the far end of the sectional on the right wall, with another lamp.

You could create the same effect with a couch and loveseat, or a couch facing the fireplace and a pair of matching chairs with a table between them on the right side wall.

The tv down in the corner to the left of the fireplace.

A chair and ottoman in front of the window, angled a bit toward the fireplace. Side table and lamp there as well.

I would put the curtain rod and panels higher above the window, as a balance for the angled ceiling.

I would keep the brick on the fireplace a different color than the wall. Leave it white, if she likes that, and paint the walls a different color. Or find two different colors that work, perhaps a pale grey on the walls and richer, deeper grey on the brick.

Decorating the mantel area will really depend on all the big pieces in the room and the style she is seeking to create. A collection of photographs or art, a larger round mirror or other art piece to bring some softness to the wall.

I would think about adding a more substantial mantel, perhaps in the same wood tone as the floor, or in black if she is going for a more modern feel. For that matter, if she wants really modern a stainless steel mantel could be great. She could also reface the brick with slate to compliment the entry, or some other stone finish.

Without knowing her style it is hard to recommend specific things to consider.

Congrats to her on her new home!

I don't like furniture blocking windows, so if it were my house, the sofa would either face the fireplace or be on the wall on the right. The size of the TV may dictate some of the furniture arrangement. If it fits in a corner, then it could go right or left of the fireplace. If it does better on a flat wall, then it would need to go opposite the windows.

There are lots of options for furniture and arranging. My advice would be to keep the profile of the furniture small - no big puffy arms or high backs. Avoid sets - sofa, loveseat, chair - and instead get a sofa and two comfortable chairs. It will give her better options for rearranging.

We had a similar fireplace when we moved into our midcentury ranch and we did not use the fireplace with that narrow a hearth. Unless the fireplace is gas, the hearth needs to be at least 18" of noncombustible material. We wanted a woodstove anyway so ended up putting in slate flooring.

The issue is lighting first of all--
I see no electric outlet in the floor--
is this house on a concrete slab or on the old-fashioned raised pier foundation where there is crawl space underneath or perhaps even a basement under this living area.
If there is access UNDER the floor it is possible to run an electrical outlet (depending on cost of course) so that you can have lights in the middle of the room...

You need table/floor lamps if you are going to "float" furniture away from the walls...

Personally I would say to have the TV over the fireplace to avoid having 2 focal points

If you put the TV on the wall opposite the large front window then your furniture would be turned away from the window AND the fireplace. Plus that means glare on the flatscreen--not the best viewing format...

If your daughter is going to go with mid-century modern look for funiture then the fireplace needs more contemporary mantle--something spare, functional--maybe metal tiles around it and sleek wood beam above...
if you mount the flatscreen above the fireplace you would need some shelving to hold the cable box and DVD and sound equip--

She should check Houzz web site for modern/contemporary fireplace photos to get some ideas...
it looks like there was brick facing on that wall that was removed
She can have open bookshelves and paint the wall an accent color or if she has ones with backs she can paint them with accent color...

I agree with not trying to block windows but you could do a reading corner on the part of the window wall closest to room's entrance--so chair could also see flatscreen above fireplace

an area rug is great for defining space--have one to anchor the larger seating group in front of the fireplace
Personally I am not big fan of one large L shaped couch because it doesn't seem to allow people to do variety of activities w/o bothering any others seated there...
So I would favor a couch with back to the wall and chairs in front of the fireplace with table/lamp between to facilitate reading...

You could also use two couches--different styles/colors even for more electic look...because if she is shopping on Craigs list she may not find two of anything...

The link I posted is search for fireplaces mid-century modern at Houzz--note that the third one down has similar dimensions to your daughter's LA--
fireplace against far wall and that room has small tv in corner
the spacing of furniture is necessary because there is no floor outlet--
and to me the couch looks oversized for the space--
that is important design aspect to consider when she is looking for furniture

good luck

Here is a link that might be useful: Fireplaces at Houzz

I would put the TV in the dark corner to the left of the fireplace.

I'd put a sofa along the long wall on the right and then I'd float a couple of club chairs with a small table in between at a right angle to the sofa, facing the fireplace.

A bench in front of the window will help complete the conversational cluster.
Add an area rug to unite the seating area and you are well on your way.

A couple of end tables and lamps would be good.

Then wall decor and plants...

She likes a transitional style with a combination of clean lines and traditional accents. She has three small children, so child friendly is also important. She will be refinishing the floor but keeping the original color of the wood and would like to introduce some color.

There is a full basement under the home.

Thank you so much for the thoughtful comments thus far.

The fireplace is low enough so that the flatscreen would not have to be so high above it but if they actually burn wood in it I think there has to be certain amount of clearance...
and you need to consider the viewing angle for one over the fireplace
too oblique an angle makes getting good sightline difficult

but I would definitely suggest getting electrician to check out adding outlet to the floor--after she decides on furniture placement so he knows where the outlet would be located...
I love having floor outlets and although we bought house without one when we bought vacation house the room is small and really can't use floating furniture...