RT Newark to London at this time is under $700 under $150 for RT Train London/Paris and unlike here- the train can be a great part of the trip. I used to get wine, cheese and sliced meat for the ride and enjoy it and te food car usually has a good meal and drinks...
It isn't al that bad at this time.
Now- Didnt check hotels but a word of warning- London for food/drink as Paris too- higher than NYC. Last time I was in London was around 2008 and just to get a simple lunch- sandwich and a soda or water- was 17 euros...
But at least, at this time, air and train are not crazy...