Though the Safe-T-Plus (not “Safe-T-Steer”) provides some basic lane control, it is purchased mostly for its incident control (eg tire blowout, passing truck, etc.) abilities. It sounds, David, as though your issue may be deeper than what Safe-T-Plus alone could eliminate. Keep in mind that just an alignment, or one done by a shop not well experienced in motorhome chassis, apparently didn’t resolve what could be a failing, unusually worn critical component.
For everyone’s safety’s sake, members here might be able to suggest an appropriate facility if you supplied your current location (Riverside?), so as to limit your highway time until the situation is successfully addressed.
Joel