Are you looking to work with a ScheduleView or a ScheduleSheetInstance?
I wouldn’t use the ScheduleView as that returns a false flag of a bounding box using the OOTB nodes. This resulting box doesn’t change or scale with alterations to the schedule - it’s a constant size - nor would it be mapped to the location of the schedule on the sheet or take into account any ‘splits’ in the schedule. There is an exposed method for pulling a bounding box from ScheduleSheetInstances shown here: ScheduleSheetInstance Properties, but the OOTB node for this fails (no idea why but you can see the source code here: DynamoRevit/Element.cs at 8e254612f9be6bdf72cb4a04a6de746ea31c6aa4 · DynamoDS/DynamoRevit · GitHub). It’s unclear how this would deal with a ‘split’ schedule (two boxes or one?).