RE: Limited DC air conditioning
A BTU is a BTU, weather it is removed bu DC or AC doesn't matter.
IF the unit is big enough to work for the area you wish to cool , it should work.
Remember the DC units on trucks usually have small sleeping areas to keep cool , and the truck will have 150+ alts , and an 8 to 10 hour run time daily to recharge the battset.
OF course many trucks will be sleeping during the daytime , and only operating at night , so the heat load on the truck will be fairly high.
Remember many of these units will need a large DC supply , solar gets expensive if you need 40-50A .