I have also managed to germinate Lilium bolanderi. I did at least know that this would be hard, so when I got the seed last winter I stratified half of it for about 8 weeks, and kept the other half in the freezer until I sowed it in October. Leaves appeared for the first time in each pot last week (at the same time as some L. pardalinum I treated the same as the first batch).
Conclusion: let nature take its course. I did probably get lucky with nature this year, as we've had 831 chilling hours so far this year, nearly twice what I take to be average. L. bolanderi lives higher and further north from me and so is probably accustomed to much more winter chill, not to mention snow cover.
Now to try not to kill it this summer.