I don’t know about them being arboreal but in nature they have to be able to negotiate rock outcrops in search of food and lodgings, many of which can be quite steep. BHPs and Womas have the same ability to climb things like rough brick walls, which you would naturally imagine they could not do. Stimi’s and other Antaresia just need the occasional crevice as they go and you will find they almost never go “bump”. In the absence of a ‘rock wall’ they will climb over, and often on, any decent sized branches.
It is prudent to include a slightly raised branch or log with all snakes as crawling over it helps the passage of food through the intestinal tract. The multitude of lumps and bumps they traverse in nature does the same trick.
Blue