Marty,
Do you have a Forest Landowner Stewardship Plan completed for your property? Such a plan would provide you with some good management direction to meet your objectives in an efficient and effective manner. You should work with the landscape in your plantings and plan the habitat areas, transition zones, winter,thermal, and escape cover areas. The rapid growing aspen thickets will suppress the new conifer underplantings. It would be better to locate any included openings and plant them with the conifers for diversity. Also remember that you should have some managed wildlife openings in your forest landscape.