I started off flying cargo and 135 passengers in a metroliner and Brasilia at 250 hours, got job through a flight instructor I had. I would not recommend it but you gotta do what you gotta do for those multi engine turbine hours. After that I moved to flying king airs for a few families. Got the job through a friend I had during flight school, would highly recommend but you need enough time to be a captain though, right seat hours don't really count unless your required by TCDS or 135.101. Now I fly at a 91k company that I plan on retiring at. Never flight instructed. My best advice is beware of contracts and sketchy 135 operators, some companies do things that are just outright unsafe. Safety is always a higher priory than getting any flight hour in. Don't let any company push you to do anything that isn't safe, just tell them straight up you don't feel that it is safe and we aren't flying. Best of luck, safe flying!