I am considering purchasing a class b rv and looking for advice. Unit 1 is a Pleasure Way Excel with Ford drivetrain, 5.4l v8 with 40000 miles. Unit 2 is a Gulfstream Vista Cruiser G26 with Mercedes Benz drivetrain, 2.7l 5cyl. turbo diesel with 60000 miles. They are about the same age, and in...