Collins at night on a weekday is usually empty. the most crowded parts of Collins at night is the hill at the top where beginners get caught with not enough speed and get stuck and the flat area beside the Easy Rider exit where everyone just picnics on. Other than those two spots Collins pretty much fits your bill.
The section after the hill is very straight, very wide, and really gentle. The snow in that section gets pretty ugly though, patches of ice, a few bumps, but its par for the course for a run that gets a lot of traffic. The run is long, constant turns will produce a run ~5 mins on average. Point it and you can go ~2 mins usually.
Panorama is slightly shorter, slightly more narrow (but not by a lot) but is more flat until you reach the hairpin, then flattens out again. The runout is VERY wide, and is usually the best place to get really wide turns going, albeit just 2 or 3 of them until you reach the bottom runout.
Cypress has really good, mild beginner runs. There's a reason why it's a popular place for beginners to go. The beginner runs are really well suited for the level, and even still the blue runs are very mild. Great mountain to progress through the beginner - low intermediate level. You'll eventually run out of terrain to ride if you want more progression, but whistler's just a drive away anyway.