The question is, is this hill any more treacherous than making this left turn? Maybe another option is just to stay on the road.

However, making turns like this can come up in many situations, so it can be useful to learn the tricks and traps. For me, if I could do it without having to come to a stop and put my foot down, I'd take the turn the same as i I were driving a car. If I had to stop with any regularity, I'd start looking at other options. If you're stopped, you're a sitting duck. I feel very uncomfortable sitting in the middle of the road at a complete stop, unless there is a turning lane, inwhich case I'd not hesitate to use it. It also depends on the speed of traffic. If it's slow enough, you're a lot safer than if it's breezing past at 60km/h+. Lane width can be a factor as well - wider lanes of course being safer.

So, if it's on a road with narrow lanes and fast moving traffic with no median strip of turning lane, I'd probably look for other options, otherwise I'd take the turn like any vehicle.

As for sitting in the left lane at a traffic light - I say use whatever lane you need, but make sure mototrists see you using that lane. Your instinct were right - it's much easier to move across lanes of traffic at a stop light than in moving (accelerating?) traffic. Sit in the middle of the lane, and stay there as you're going through the intersection. Move to the edge of the lane as you're coming out of the intersection - in the case you mentioned above, move to the left side of the lane to allow cars to pass on your right. It can be nerve-wracking at first having cars pass on the 'wrong' side, but you get used to it, and you'll find it's no different than cars passing on the 'correct' side.

That said, I really can't say exactly what I'd do in the specific case you mentioned without a clearer idea of road/traffic conditions, but for me, the footpath (and bikepath for that matter) is always the last option. If it were me, I probably wouldn't make the turn at all and stay on the road.