Handyman advice needed

OK, calling all you cabinet makers/carpenters/timber experts. I am in the planning stages of making a slide in kitchen for my new camper trailer. It will be as long as the trailer – 2 metres, about 37 cm wide (to still allow 6 x 60L tubs in the trailer) and about 45cm tall. It will have various shelving/dividers to act as supports, and will want it strong enough to carry various food/cooking items including cans of baked beans etc.

Question, what timber should I use and what methods should I adopt to ensure it’s strength? It will pull out and be supported by a couple of extendable poles on its end, and slide out with about 30cm remaining on the trailer. I’m thinking about mounting a bracket underneath for another supporting extendable pole ½ way down, although it shouldn’t really need it.

I’m willing to paint or varnish the whole thing, and probably put stainless steel across the top. It will not be left out in the damp or rain, but want it to be slightly water resistant and I hope the paint should help with that (undercoat and 2 coats of enamel)

At this stage, I’m thinking 19mm ply on the bottom, something similar on the ends but in MDF (easier to screw), maybe 12mm on shelves/vertical supports, and thin plywood on the back, with thin ply on the front doors which will open and swing downward on hinges (magnetic latches). I want to both glue and screw joints, and maybe even partially frame it in places where higher strength is required.

Anyone got any thoughts or adjustments, because I really don’t know. I want to keep the cost down but am prepared to spend $400 or so all up.

Thanks

D-Jack