Welcome to DC jcv....For "in the house" or big green egg I would recommend the Lodge 5 quart (10-1/4 in) "Kitchen" oven (No legs)...Number L8DOL3...It has loop handles that will make it easier to go in and out of the oven...Weighs about 14 pounds. There is a 7 quart, and 9 quart model, but they weigh considerably more, and have bail handles instead of loop handles....
For camping I would recommend the 12 in. 8 quart "Camp" oven...It has three legs on the bottom so it will sit over the coals...also a flanged lid to hold hot coals for baking etc. It also has a wire bail handle for hanging over the fire...There is also a 12 in. 6 quart "camp" oven that makes a great baking oven, but can sometimes be a little too shallow (3 3/4") for other uses...The 8 quart is the best all around, all purpose "Camp" oven IMO. The 10 in. 4 quart gets small real quick on/over a camp fire.
Lodge Pro Logic cookware is "Pre-Seasoned"...but you will need to season it a couple of times before use...HTH
PS....Repeated braising (cooking with liquids) pot roast etc will degrade the inside seasoning over time...Any type of acids (tomatoes) are especially hard on the seasoning....Remember cast iron loves oil/fats...Plan your menus around braising sometimes and frying fish, chicken, bacon etc. at other times. Baking is good for seasoning as well...just lightly coat the inside with oil prior to baking your biscuits, cornbread, cake etc.
There is only one Quality worse than Hardness of Heart, and that is Softness of Head.
Kool-Aid...Think Before You Drink