I personally would steer clear of 135 freight. I did it for a while and didn't see anyone leaving for anything other than the regionals. I lucked out and landed an awesome corporate gig and was able to leave without taking a pay cut. I ran into a caravan pilot a few months back who was talking up all his hopes and dreams to go to FedEx and planned on doing so with his 1000hrs TurbinePIC in the van. I had to snicker a little.
Just because you flew some boxes dosn't mean that UPS wants you more than a pax 121 guy with turbo-jet and glass experience. You will be competing with 4-5000 hr crj captains who have been waiting in line for a while now.
Corporate is all about who ya know. Period.
Apply to both dude!
Good luck