Originally Posted by
PsiFighter37
BUF-EWR is likely on UAX; all UAX departures are now out of Terminal C (I do not recall seeing anything other than mainline out of the new Terminal A). As such I would think transiting with a wheelchair will be easier in EWR because there will be no terminal change.
On the way back, I think it won’t be pleasant either way because you will have to re-clear security no matter what.
Currently, there is an early morning flight on mainline, but I am assuming OP would be taking a later (regional) flight to minimize connecting time.