Would like to be a courier So Cal to New England this spring

I don't think you will find many, if any, interested in your deal.

If I'm understanding your post correctly You're planning on allowing your aging cat to walk around the RV while traveling because it can't be confined to a crate?

Good luck and, enjoy the trip if you find someone willing to take you up on your offer.

You will probably be better off making the trip in a car.