We aren't talking about a plain 1948 Ford pickup frame here where they are rectangular simplicity. We are talking a very complex frame under your Chevy. And if you think "body mounts" are the easy part, pile that on a list a mile long from steering column mounting to bumper mounting, to the floor hitting the frame the rad support needed to be cut up to clear the frame.
"Can" it be done, well certainly, but so would be using the fender on from the Ranger on your Chevy, you COULD modify the fender from the Ranger to fit, but it would be much easier to make one from scratch.
There is no such thing as a frame "swap" using the wrong frame, is using the wrong frame. What it does is "swap" money from your Chevy frame to the Ranger, "swap" time from your Chevy frame to the Ranger, and "swap" work from your frame to the Ranger frame.
What are you after with your Chevy, what are your plans?
Brian