Would like to bring to potluck in one pan. What size pan would work best? Has anyone tried this?

These are great ideas! Here is a link to the sheet pan crisp recipe: https://food52.com/recipes/82168-sheet-pan-apple-crisp-recipe

and here is a pan with a covered lid that would retain heat well: https://food52.com/shop/products/10053-le-creuset-rectangular-stoneware-dish-with-platter-lid

Another approach - use the sheet pan apple crisp recipe here for a larger # of servings and baking times.

You could still use the original recipe for ingredients and multiply them for volumes.

I’d try a 2 quart baking pan.