Hi! I don't have a response to your idea concerning dowries (however I think it's a great idea!) but I did want to mention that you've inspired me to start my own RKC!
I want to do a more fantasy type kingdom filled with supernatural sims and elves (basically human sims with pointy ears I guess) but looking at Castle Keep I would have to change too much of the setting to give it the fantasy look I want. I found a great post
here about altering Dragon Valley into more of a fantasy setting so I'm going to start with that!
I believe you mentioned on your blog that you don't use CC (or very little anyway) yet your sims look fantastic! Do you have any tips/tricks to share about what you do use in terms of outfits/hairstyles/accessories/etc. and where they're from? :)