I understand that Toaster, at the moment, does not have the ability to run the generated images on simulator, quemu or something else, with the click of a button. Hob had this feature, at least for qemu, I think it would be usefull to keep it. For Hob and running with a custom simulator, please check: https://bugzilla.yoctoproject.org/show_bug.cgi?id=8940
*** Bug 9453 has been marked as a duplicate of this bug. ***