On the roping rein front, since I usually leave a halter on Lacey anyway (being nearly blind, it's MUCH easier to lead her by holding on to the part of the halter under her chin - so she knows where I am at all times), I just clip one of the snaps on the reins to the halter and hold the excess rein like it's a really long lead rope. I've also "tied" her like that (I never really tie her to anything out on the trail, I'll wrap the reins/lead rope around something but no solid tying) without issues. However, Miss L is one of those "oh, there's slight tension on the line when I move this way? I'm OBVIOUSLY tied and I OBVIOUSLY can't get away." I'd imagine that if Sky's a little less docile about tying, that might not work as well.
I can understand not wanting to leave the halter on though. I dislike the look of a halter plus bridle but since I don't really have a choice anymore... haha