For a novice painter such as myself, which is the best procedure in repainting an already occupied home? Sprayer or rollers and brush?

My project is painting lots of windows 3-4′ wide and 6-8′ tall(6″ trim), doors (6″ trim) and base molding (8″ and 10 “) in a 100 yr. old house that currently has semi gloss paint. Are there any primers that really work where they state you can prime over gloss

We have several small gouges on the painted indoor wood trim surfaces, window sills and floor molding. Would like to know the best way to prepare (before painting) indoor wood trim, door trim, floor molding, etc that have small gauges or indentations from years of children banging things into them.