The winch can be relatively small, you are not lifting the trailer just pulling it.
if the poles of the carport are in concrete in the ground, they are likely strong enough. Otherwise, a steel stake used to hold concrete forms driven in the ground at angle opposite the load will hold the winch.
A dolly wheel instead of the flat plate for the tongue jack and I think you are set.
Jeff & Cindy
'09 27FB Flying Cloud
'91 350 LE MH