Ahhh, you can go ahead and paint just put some lil heaters in your trailer or get your shop nice and toasty...it'll take more time than you think to get it ready if you take your time and plan it out like you want. Bedliner the floor and good exterior paint on the walls, and go from there.
Where did you go to get the Lark trailer? What in particular did you notice that you didnt care for? How much did this trailer run ya?