The biggest issue you will run into is the thickness or jamb width of a replacement patio door. You will see most of the house versions at the big box stores will have a standard 4 - 9/16" jamb to fit a 2"x4" wall. (Your trailer door and wall will be much thinner) The other issue will be the height of the door, it will not be standard either. You might be able to order a mobile home door through them but you will need to measure the frame thickness and door height / width in your park model. Another issue will be replacement or new construction type.
Your best bet would be to have a window and door company order and install it for you, they have access to custom doors. Should cost around $1500 installed. Keep us posted.
2017 Salem Villa Estate 395RET-
2011 Coachmen Freedom Express 295RLDS- Sold
2015 F-250 FX4