Siding Recomendation ?

I have a hand-built truck camper I purchased from the builder. It is built very well, but he ran out of money and time when he got to the exterior. There is Luan on the outside now, painted. I need to put something over it, or replace all of it. I don't have a ton of money to put into the project at this time, but want to put something on it that will last. I store it in the garage, but use it in all weather.

Open to any suggestions you have

Thanks

Shortbus