edit: fat charlie beat me
Driving without brakes (DWB) isn't completely doable. It should really be called driving using the brakes as little as possible since you can't eliminate using them entirely. Every stop you make you use brakes, you just need to. If you can coast down from 45 to 25 mph before a stop thats pretty good IMO. The slower you coast down the better obviously.
I coast a fair amount in automatic transmission cars. The real test is when you put it back in gear (at speed), does it lurch? If it does, you can try to rev-match to minimize the lurch (I do this). Or, you can coast in gear (least efficient).
Idling in drive always uses a bit more fuel than shifting to neutral. On my Sunfire its about 8% more .