Are you talking about just using castle brian rules to make the station? Or are you referring to some set of rules that is similar to castle brian rules that already exists?
If the first, it's completely viable, but you would need something on it to supply station keeping, since castle brian rules don't include anything for station keeping. You would also need something to hold it all together while the station keeping drive is running. Unless you built it in the space between systems.
For record keeping purposes, a station would be much easier to keep track of than a castle brian, since one you have to track hex by hex and the other you just have one statblock (or 3) for the whole mess.
If you are talking about the second, please point me towards those rules, because I am not aware of them (even if they are from someone's AU, I'd be interested in taking a look at them).