Welcome to the forum!
What is 'easiest' is to find a car with no rust to start with, so you won't be pulling your hair out later on fixing sheetmetal.
That said, a car that runs is easier to inspect, because you can drive it--you can see if the suspension and steering are ok, etc.
Be warned that the swap cna be done cheaply, but it can be a money pit if you are not careful. These swaps are not for the faint of heart.
Buy the JTR manual, if you have not done so already, and read it cover to cover at least twice. That book will put it all in perspective of the necessary steps of this undertaking.
www.jagsthatrun.com
Good luck,
Davy