The roadmap for the basic browser is still largely as OP (Initial Development Goals).
This part however:
Is looking more like, ‘enable API access via a browser global variable for SafeSite/Webapp access to the API’, probably via an updated version of safe-js at this juncture, though that could well change.
The stretch goals are somewhat harder to define, and have been pretty well debated in this thread. How much ‘launcher’ and ‘api’ access should sites have, and how to do it is to be decided still. But initial base ‘browser’ specs are as above.
As for timeline. I’d hope for to have testable beta implementations inside of a few weeks. (I won’t be able to go full time on this, but will be able to dedicate at least 2 full days a week, as stated in the OP). Other factors such as an upcoming holiday for a week might get in the way a bit.
Even with that holiday, I’m aiming to be well inside of the original (approx) timeframes set out in the (CEP announcement)[Community Engagement Program v0.3] (6 weeks), from when I fire in proper.