Well, ideally, you would shift the track pair to hug one curb, either the north side or the south side, and then eliminate the direction of traffic on the side where you shift the tracks toward. So, for example, if Queen was turned into a one way westbound, you would shift the tracks to the south curb, so that the current eastbound parking lane effectively becomes an eastbound streetcar ROW with boarding directly from the sidewalk and the westbound streetcar line is the non-ROW, left-most lane of regular traffic heading west. You would have to create an island platform for the westbound streetcar but that would probably be easy because you would just shift the car traffic slightly to the north past an intersection (so the rightmost traffic lane would take up the parking lane for the section where the streetcar platform/island exists).
Man, I wish I had better illustrator skills so I could actually draw this arrangement.
Anyway, this is still incredibly cumbersome because you would have to rebuild the tracks and all of the Grand Union interchanges on both King and Queen. It would cost several hundred million dollars and it would probably be more effective to just build the DRL and pedestrianize portions of King or Queen.
Personally, I'd just rather see both of those streetcar services switched to Richmond and Adelaide. Right now they just crawl along, but if you put in streetcar tracks on the right side of both streets, people could board right from the sidewalk, and because it's a one-way the streetcars may actually move.
That way you can do some changes to Queen and King to make them more pedestrian friendly.