Is there a BIPs roadmap somewhere?
All the BIPs that have been written up are listed on the BIPs Github project along with their status:

https://github.com/bitcoin/bips/blob/master/README.mediawiki

There's rarely a clear plan as to when they're going to incorporated into bitcoin-core and the corresponding schedule. In open source projects, features get incorporated when someone gets around implementing them and the review process is done.

The best way to follow implementation is to follow the development mailing list and Github pull requests (https://github.com/bitcoin/bitcoin/pulls).