My most productive times caching, and the most enjoyable, and eco-friendly, were caching the Power Trails in Montreal. Along hiking trails in the parks caches are spaced between 160-200 metres apart. Makes for a nice diversion along the hiking trail. I particularly appreciated not having to get in the car every 10 minutes to get to the next cache.
I'm thinking that the cachers in Winnipeg could cooperate with the hiking association to cache along city trails.