can't help with your mounting- I have a PW.
the TV I bought at costco for under $130 is a 21" samsung which runs native on 12 volt...for home use it comes with a brick type ac/dc adapter.
so a winner for power consumption as it doesn;t need an inverter and the parasitic losses converting dc to ac.
it also has a Media Player which will play most digital video formats- I put movies etc on a thumb drive and plug into the USB port.
the channel autoscan is easy to use ( I use TV Towers app to point the antenna)
this tv is also lightweight- on the PW the TV is mounted on a swinging door so can be pointed forwards. I made a bracket with some steel strapping from home depot cost about $3.
you may be able to look at mounting arms for computer monitors...the tv mount lugs on TV's are pretty standardized
here's a link to some pics maybe that'll give you an idea for your van: