Regarding painting, The scenery is all set for painting, no prep necessary! TBH you don't even have to bother with an undercoat, we have already pre-sealed everything! This stuff takes paint really well but because I work mainly with the airbrush I like to start with a black undercoat and work up through the colours to brightest, let the black work for you with shading! I have always steered clear of the expensive 'modelling' sprays and found that acrylic auto spray is perfectly good for the job and usually much cheaper!
Each scenery piece is cast using high quality Alpha grade casting plaster. This is one of the highest rated materials made by special formula, it is a very hard, white 100% Alpha plaster for use where high strength and surface hardness and durability are important. This is a much harder material than resin as it holds great detail and does not suffer from bendy sword syndrome. Every scenery piece is cast by hand so may contain small air bubbles or imperfections that can be solved with a little TLC.
This material usually repairs seamlessly, I know, I have dropped plenty with my butter fingers and just watched one of my new rivet wars trains bounce down the stairs, now repaired with the aid of the good old superglue and a lick of paint...good as new!