Ecam321,
I'm not an expert on recruiting but have certainly heard of 50 y/o people getting hired at legacy/LCC carriers. I don't know what percentage of new hires that might be but it does happen.
I'd advise you to apply to everyone you might even be remotely interested in and see what your options are. I'm not sure a Part 135 operation would give you the time off/schedule flexibility you want. From what I've heard, I think those pilots work pretty hard.
As for bases, Google "airline pilot domicile map" and see who might have a KLAS base.
Good luck.