Saw a show about Solar Cookers on Dish a few weeks ago and they were teaching women in Africa (I think) how to cook with them and they were just cardboard with something like aluminum foil on the inside of them and they showed them how to set them up, how to use the plastic bag around the pot to make it keep in the heat to cook the foods and they said that the food wouldn't over-cook in one. I thought it was some good info.
We like to cook outside on an open fire in the summer, have baked bread, pineapple upside down cakes, a lot of different things on the fire. Just like camping only you don't have to leave home to do it.
We used to roast chicken and hams on an open fire, turn it by hands, no electricity or battery power for us, we liked to do it the old fashioned way, now we are getting lazy, and have a battery powered rotisserie and we have went back to the hand powered one, for we liked the way the chickens cooked better, they got done faster, as they weren't turning around so fast and the heat could get to them quicker.
If you find a site that tells you how to build one, let us all know, for I would like to have the plans to try myself this summer. I too live in a trailer, and when you cook inside, the house is so hot, the A/C runs all the time. What a waste, or electricity. either cook or cool, no happy medium.
...and may the Lord bless us, with all we need. AMEN