Try this, I read subcool talking something about it.
Take the LR2 female and pollinate it with the male Northern Lights. In theory now it's 50% LR2 and 50% NL. Now while keeping that male alive, you grow some of the seeds from that pollinated plant and pollinate it again. Now the seed grown that was 50/50 that you just pollinated will create seeds that are 75% NL 25% LR2. You keep doing this until it is about 90-95% NL by now hopefully none of the autoflowering genetics are crossed over.
Now to get fancy grow tons of those seeds and find the best males and females and selectively inbreed and after a while you'd have yourself some NICE genetics.
BTW I think it's a great idea, the strain I'm growing now (and you can check out my journal) is Northern Lights x Lowryder x Hawaiian. It's amazing.