There are quite a few good Polish restaurants on the northwest side that have a primarily Polish-Polish clientele but that have very little coverage on LTH or CH and no coverage in Metromix. The buffets are Polish-American and unknown in Poland. Red Apple seems like the Polish Maggiano's Little Italy (quantity over quality) but with only two locations.
A sample that are relatively easy drives from Rosemont: Smak Tak, Hortex and Smakosz. I have been impressed with the food at Smakosz but haven't had enough to feel comfortable starting a thread on it.
Belmont Central has a bunch of food businesses but is more of a drive from Rosemont. Lutnia is more upscale Polish, which tends toward continental, and is a class by itself. If you go to Lutnia, there is a free multilevel parking garage on Central a half block south of Belmont. More Polish restaurants in the Belmont-Central area include
Barbakan and Retro Cafe aka Retro Bar and Grill. There may be a language problem at the latter unless somebody in your party knows the Polish names for foods. I have not been there recently, but the menu had almost no English translations or descriptions when I was.
Smakosz
5619 W. Lawrence Ave. (4800 north just west of Central)
Chicago IL 60630
(773) 205-1771
Retro Cafe
3246 N Central Ave
Chicago IL 60634
(773) 777-7715
Barbakan
3145 N Central Ave
Chicago IL 60634
(773) 202-8181