My 2500HD chevy and 915 Lance near Colima, Mexico.

Remember any added weight on the truck subtracts weight from your payload.
A one ton truck is better for a diesel and four wheel drive and a slide on camper.
Gas engined 2 wheel drive 3/4 ton trucks work well.
You will love the power of a diesel and hate repair costs.
Never found any diesel pumps in Mexico with small truck sized nozzles, have something for wiping diesel spills from the side of your truck. Most fuel attendants will spray water on the spill for you.
My old 2003 Duramax ran better on Mexican fuel.
Buying that truck again it would have the 6 liter gas engine and I'd still have it.