Hi Randy;
So your thinking an 8" batchbox! Just how big is your camp? cathedral ceilings?
My auto shop is 24 x 32 with tall ceilings. I built a 7" Batchbox for it on Peters recommendation, as in his words an 8" Batch is a beast!
I am very happy with the 7" version. Peter was correct (as usual) the 7" was plenty for my shop.
So, no matter what size you or a contractor build, there are some supply's that you will need. And some you might want.
Sounds like you have plenty of bricks. Being a fireplace hopefully some of those bricks are fire bricks and the rest are clay brick. Concrete brick is a poor choice and only usable down very low in a bell.
You will need several #50 sacks of fire clay. You will need sand, a LOT. Three times the amount of clay. Sharp sand... unfortunately ocean beach sand is super fine and small. It could be used but is a poor substitute.
If you wish to build this to the absolute best you can. Then you will want/need 15-20 Insulated firebrick's good to 2700 F. (Highly recommended)
You will want Morgan super wool ceramic fiber blanket to build a five minute riser. You may want some 2" ceramic fiber board as a roof on your box.
You will want angle iron to build a support inside the brick bell. This will place your batch box up off the floor but completely inside the bell and make loading easy for an adult and place it high
enough that little ones can't touch it.
About an oven. If you build a batchbox with bell. You would need to build in your own oven. Could be done but adds more time consuming masonry work.
An external cook surface could be easily incorporated into a bell.
Now , Matt Walkers large stove is set up with a black oven and utilizes his riserless core. He
sell complete plans with a total build list of materials.
Another thing about buying plans from Matt, he is super friendly, super knowledgeable and you get unlimited free build advice, thru email or phone if you run into difficulty.
I have no idea of his costs but Matt will travel to build for you if that is something you might consider.
Thats enough for now. Let us know what your thinking.