Back when I flew Part 135 (Be C90 & A100) with 2 flight crew - it was "why bother checking the weather? You gotta go anyway"
Hope you are light enough so you can load on the fuel and find some kind of legal alternate - for departure or destination.
It didn't hurt that we flew out of Northeast Ohio (for many years). As long as mountains weren't involved, we had pretty good experience with anything that was likely to come up.
Many times one guy would fly the approach and the other would ID the runway environment at minimums and make the actual transition and landing - it worked well for me and the guys I flew with.
Every deadhead leg was used as a training opportunity - had to do so anyway, 6 month checks came around awful fast
Embedded TRWs without the Wx radar was something we did NOT feel casual about. Can't remember the radar being out all that much though.