Why do warm temps concern you? From here on out the skiing will not be good without warm temps. This is the time of year to skip first chair and not get on the mountain until after 10.
^ This.
Why wouldn't you want warm temps in April? Warm temps this time of year is what you want. Not warmth like 60's or 70's or 80's, but days where it doesn't get above freezing are probably going to be less than great since there has been thawing, re-freezing, rain, etc.
Also, I believe caribchakita mentioned she had a free room at Sunday River... was it for that same weekend? Why pass up free lodging?
As far as open with best conditions the 14th/15th - probably Sunday River, Killington, Sugarloaf, Sugarbush, Jay, etc.
However, Killington will be open well into May, so I'm trying to reserve at least 1 MAX Pass for when its just Super Star.
If the 10-day Weather Underground forecast is accurate, next weekend should be a blast everywhere with temps hitting mid/low 50's.
Personally, I have 4/16 off and was thinking of using a MAX Pass ticket at Sunday River.