I feel your pain!
My wife and I are in our late 30's as well with two young girls (6 & 1). When we originally purchased, only SSR and AKV were available. We purchased SSR thinking that it was slightly less money then AKV, and had more amenities available (aside from the animals). In thinking long term we thought we would get more out of the spa and DTD in the years to come then AKV. Also liked that the pts to stay at SSR were less than AKV. While we would try other resorts we tried to base or purchase on how many pts at our home resort.
My advice would be to decide what is MOST important. I know this is a hard one and was for us. I am one who likes to maximize the amount of days I can get at disney. Unfortunately that meant BUYING more pts then we originally planned now that we own BLT. If going often or for more days is the most important factor then SSR is the way to go. If it is convenience or the place that really hits home, then maybe BLT. Although make sure you understand how many nights it will get you and don't go by how you travel now. Look big picture. When we purchased we only had 1 child and only traveled Oct-Dec. Now we have 2 kids and go anytime throughout the year. Our original purchase of 200 pts would not have allowed us to travel in the spring and we didn't think about changing plans back then. Hence the add-ons!
If you go the route of splitting contracts, just look at what borrowing/banking gets you. Not sure how many BLT you would get for 1/3. Is that enough every 3 years to get what you want?
Having owned both I can say, if you go the route of SSR, you will not be disappointed. It is a BEAUTIFUL resort. VERY relaxing. Has great amenities for the family, gorgeous landscaping, walking distance to DTD (which looks to be really cool once they complete the changes). The only drawback is that it is a little further then some resorts. If you take the bus that is some added time you need to consider in traveling.
If you go the route of BLT, it is AWESOME. For us there is no better place to be. You can walk to MK, take the monorail to Epcot. The resort is beautiful and the Contemporary holds a special place in DW's heart so that added to our decision. Nothing beats being on the monorail and having access to the Poly, and GF as well as BLT/CR. It is like having all 3 resorts. You can get to any of them so quickly and it opens lots of options. Also with kids it is so great not having to take them out of the stroller to get in a car or bus. Of course they are only in a stroller for a few years, but still great.
For us, we loved SSR and enjoyed our time there and will stay there again at some point. However, from the minute we walked into BLT/Contemporary, it just felt right and like home. I never understood that when people said it before until that moment. We were there 10 minutes and DW looked at me and said "we are adding on here before we leave".
Would it be possible to take a trip and try both resorts? Also don't forget, while you may not be thinking it now, you can always add-on later if you need.
Not sure if I helped at all. If you have any specific questions about either resort let me know.