To answer some questions...
No other routing they were willing to rebook me for that night, since CO had no more flights to Vegas I could catch. The gate agents were rebooking all the passengers even before the plane made it back to the gate and I was already booked on the morning flight of EWR-LAS. But another carrier? I got a major "no".
As for as EWR transit - I made it, no problem, on Sun even though the BOS-EWR was once again delayed on departure and the scheduled transfer time was <35 minutes. I travel light - carryon only.
$150 is combined cab, hotel, car rental additional expense.
Thanks fro the suggestion - I'll collect the receipts when I get back and fire off a 2nd message if CO doesn't respond.