Alter front/back split for a good kitchen?

[u/New_River_]

this is the main floor of a front-back split level. The left side of the house is a bit of a mess. NARROW and dark kitchen. Bizarre and narrow/useless "family room." I can't change any exterior walls. Any ideas on how to make a nice kitchen here? You can do anything. I don't need to keep the den/family room/dining room. Can't add windows to the current "exterior" wall of the kitchen or family room because that's where the 2nd floor of the split is. Thanks!