Are there non-reserved seats on the N'EX? And what is the cheaper bus to Shinjuku? (I know we've seen some discount bus lines emerge - and I know there's been a discount line to Shinjuku in the past - but I'm not sure if there's one now).

OP - I've taken the 1,000 yen train a number of times. Back in the days before the new Keisei Skyliner, the slow train often arrived at about the same time as the fast train that left NRT 30 minutes later. So, I'd often take the slow one and never regretted it. The trick, if you have luggage, is to snag a seat at the end of a row, so that you can place your suitcase in the space between the end of the row and the door. (Put it on its side so that it doesn't roll around). Avoid the silver seats, because you're expected to give those up for people who need them more than you. All in all, it's a comfortable, but rather slow, ride into Tokyo.