Why 2 entrances to guest room? I think some pics would be better than the drawing which i find hard to read .Have no idea of size of room and a sectional IMO would be the last choice for furnishings especially if it has to sit i front of fireplce at all.

most encourage 2 couches rather than love seat. provides more seating without much additional space used. Sectionals also not recomended. If your children are old enough to prefer sitting in a chair, you would probably want 2 couches and 2 chairs. are you do formal separate from tv? might wish to think about it. maybe put the family tv room over in the sitting area? regarding the entrance way, i always prefer having it separated especially if the family room is first room they enter. at the moment, i would do an l with the sofas and then have the 2 chairs. 2 have 3 sides facing the fireplace, with tv next to it. you might then wish to have another small sitting area in front the windows, that then can be brought into the grouping when necessary. did you wish to anything else in there? office space, game table?

Which door is the main entry into your home? Do you use the second entry? Post some photos so we know how low your windows are. You first need to determine where the TV can go. If you put it on the longer 10 foot wall you can use a long, very narrow, console table beneath it. Then put a sectional in the other corner of the room, possibly with a narrow sofa table behind the main section, in front of the smaller window. The chaise part would be partially in front of the longer window.

Congratulations on your new home! Your fireplace hearth is likely 18-21" deep and the step 10" leaving you only approx. 8 1/2' to create the desired cohesive seating area around the fireplace you desire. If you were to float furniture facing the fireplace and found a shallow sofa of 36" depth and left the 3' of flow/walking space behind it that would leave you approx 29" of space in front of the sofa until you hit your hearth. Sadly due to the depth of this room and the length and the other factors listed above it doesn't lend itself to an arrangement around the fireplace. Placing a TV above the fireplace would mean anyone viewing it will be watching it from the side. Your friend here is going to be the swivel chair, I would do 4 of them two on each side flanking the fireplace. I would think of this room for entertaining and conversation. The wall the sofa is currently sitting on I would do a bar wall. I pictured a modular one here that can be added or subtracted to. Having height is a good option since that wall is your largest feature wall. I would flank a round coffee table with four swivel chairs on each side. If you want a TV over the fireplace (although I think its crying for a wonderful piece of art) you your at least turn the chairs towards the fireplace Anchor it all with a 8 x 10 rug add some cocktail stand tables between chairs. I chose these because you wont have room for much more since you wont have a lot of table space I would install a nice lighting fixture over the round table centered on the fireplace to bring in lighting I would dress the windows as well as the slider with some nice neutral drapery panels. Mount them as high as possible and hang them so they are 1/2" off the floor.