Thanks for all your help, it's appreciated. What raised the question is on the Lifeline site (one of two brands in consideration) they state ventilation is needed which is a bit different than what I thought.
The trailer is mostly 12VDC, for inverting to 110 it will me mainly TV, DVD, coffee maker and occasional microwave (most due to the light and vent being 110). When dry camping we cook outside and can make coffee on a camp stove but retirement is 15 months away so that could change and planning for that as well.