microwave recommendation - and crate dimensions

Small 700 watt microwave is what you want. Too big a draw on power may interrupt the inverter.
As far as a crate for dry food, I just use grocery bags or any old box. The truck should have plenty of storage cabinets. I mainly just eat ravioli from cans and microwave it. When i am making my own meal I should say. Clean the bowl and spoon immediately after with a dry shop towel. Makes for a decent meal that costs very little. You can do soups as well. Also can carry a box of cereal and just buy milk from wherever. Same trick clean it immediately and it's ready for the next time.

 

For a microwave, you want to look at something like this.
Mostly it is the size, it should fit in the trucks cabinets.
With something like a microwave used with a power inverter, you want to have at least 2 times the rated output. 700 watt microwave needs to run on a 1500 watt inverter. The reason is it take 2X more power to start it.

https://www.amazon.com/Bella-700-Wa...n_feature_keywords_four_browse-bin:7801527011

 

Keep the total wattage as low as you can. For every 100 watts you are using there is 8.3 Amps at the battery. Look at the chart a 800 watt microwave is using ((70)) amps at the battery!