Ouch! That hurts! I just did the same thing, put a stairway from the basement out to the garage. The main reason is because my 'winter workshop' will be in the basement and the garage stairway will save the house stairway the wear and tear and DIRT that I seem to alway track in now! Regarding egress, basements here require egress windows to the outside for bedrooms only. I have seen many spec homes built with huge basements but no egress windows for future bedrooms after someone moves in and finishes the basements. All in the name of saving a few dollars up front, I suppose.

Local codes do vary. Most likely a configuration like yours could not be constructed today. To begin, carbon monoxide settles so the garage would need to be LOWER than the basement, not at the same level. But, due to the age of your home, codes from the time of construction are most likely grandfathered until MAJOR reconstruction is undertaken. I have no idea as to whether opening the old doorway would qualify as an escape route. An egress window, even through a window well, would be acceptable so if you could enlarge a window, removing your deck would not longer be an issue. You would need to check local codes for a size requirement. This is especially important if sleeping arrangements are part of your basement usage. Hope this is of some help.

I imagine that the expense of the grading, concrete, well, etc. will amount to a project of some significance. At that point, the window should only be a very fractional portion of the project/labor totals. If there is a good match to the profile in vinyl, that should be fine, but I can't imagine a different product really moving the needle much on the total price.

Wow. You guys are awesome! After talking it over with my husband - we decided on swapping the playroom and office. We will also add double french doors that can bring light in to the entertainment area. We do need that full bath as my mom will stay with us (weeks at a time from overseas). The playroom will be at the bottom of the steps so I can peak on the girls while im upstairs clean/cooking/doing whatever. The staircase will be open so we can pivot furniture. This will bring light in immediately as well. Under the stairs will be added storage for their art supplies/school supplies...etc. The bath will be right off the bottom of the steps so people can quickly access the bathroom if the powder room is occupied upstairs. It also removes the bathroom from being open to the entertainment area.