Hey Mike,
As an added note from a personal point of view - I NEVER use particle or chip board where plywood or solid lumber will work (especially due to weight vs. strength and stability. Because of this, all the wood in my trailer is board lumber and plywood

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I ran out of time due to a move and ended up using a recycled piece of 3/4" plywood for the counter top. Just because I want something that looks a little different, it will be changed out to a glued-up plank at about 3/4" to 1-1/4" thick (I have a bunch of oak that may get used here as I have a surplus of 1x4's (That is full 1" by 4"). If planed, jointed, ripped, and color selected for contrasting color and grain, a counter should look nice. The plywood looks and works fine, but after this move, the cargo trailer will be retired to be my winter travel and prospecting lodge and I can afford to take more time in building/modifying certain areas.
In addition, my 6x10 CT weighed in dry (before my additions at 1400#'s); adding the galley, shelving, 5 gallons of water for sink, Ice and food, camping/prospecting gear, propane bottle and Grp 27 Battery on the tongue, charger, and inverter, etc. the weight starts up quickly ... I use this where a 4x4 vehicle is needed and weight consideration is a must!
Anyway, just thought I would add this note and state that lots of folks use pre-built cabinets (and they work and look great) and for cost and material I chose to make my own (Not as nice as a custom shop would make, but acceptable to me), I am also cautious with the wood and strength are concerned.
Good luck...