Train newbie- could use some advice

Hello! I’m an AFOL and MOC builder but I know nothing about Lego trains. I do a side gig with a local Lego master who does educational stuff in schools and he asked me to rough out a track layout for an upcoming school build. The idea is to leave bunch of blanks spaces for the kids to build bridges over. 14 tables and 21 bridges. Multiple levels is allowed. I’ll take a pic of his layout and show you also his bridge he built for another school that we will reuse. I don’t even know the right...