Grasshopper Freeform Underground Club 3d Modeling

Hey guys, making this underground bar shape coming true, started with grasshopper, and now continuing with SUBD rhino 7, though its not so easy to model seating parts and tables, as it gets twisted because cant keep parallel iso lines…I am also trying to connect the entrance tunnel together with the club.

Was expecting to generate a full grasshopper algorithm, but I got stuck… Any suggestions? Both for Grasshopper or/and Rhino modeling?

thanks a lot!!