I have ADHD as well. I found that while cutting out distractions is helpful it's not enough as I will find distractions as soon as I'm bored no matter what. Living in a TTY only environment would be limiting to my productivity because I cant search the internet as effectively and then you'd have limited your productivity in one aspect in order to increase your productivity in another.
Also I have wasted a LOT of time "optimizing" my workflow over and over again. Only to see benefits so marginal that the time I put into setting it up was never recovered. My advice would be to find a middle route. Block some websites maybe, create a "work only" user profile so if you want to game you'd have to switch profiles and such. But more importantly find other tools to help you with your productivity as well.
Do you set yourself realistic short-term goals (for the next hour, this afternoon or whatever)?
What's your reward for accomplishing them?
If you find yourself in a distraction (it will happen no matter what) how can you reorient yourself? I found a traffic light I have on a card on me helpful. Stop, decide what I want to do, go ahead and do that. If I really need a break I can take it in the knowledge this is what I decided to do. Or I have to choose to go back again. Other methods could be a pro/con list or verbalising what your doing vs what you want to do. The point is that the decision should be made consciously and that you hold yourself to making it and dont avoid it.
I also try to make as many decisions as I can beforehand. What will I do today? When will I do it? Planned down to the quarter hour as much as possible. I write my plan for the next day the evening before and have a weekly schedule for all the routine stuff and as a framework for the minute detaild. Eliminating spontaneous decisions wherever possible has been the best tool for me to accomplish my goals.
Obviously I can speak only to what worked for me. I can highly recommend seeing a behavioural therapist who can work with you to develop your own custom tools in dealing with ADHD. In my experience setting up some idealized work environment won't be close to enough however. It is fun though.
Edit: all of that said, Emacs can do whatever you want it to.