I have a charmglow Elec TF. I would think the best approach would be to convert a small cheap cooler to use a a MT. Use the fryer for a HLT and boil kettle.
Or if you want to keep it simple, maybe mash in the fryer w/ a grain bag, and proceed to boil in the fryer. The thermostat on the fryer is not at all accurate and likely cannot be relied on. If mashing in the fryer, you could also try simply wrapping it in a few blankets, or removing the inner pot and placing it in a wram oven to retain heat.
Be warned, the power of these fryers is very limited and it will be slow. You will likely need the lid to reach a boil, and the lid on partially to boil. Not ideal, but it will work IMHO. There is a thread that claimed good results by insulating the outer shell b/w the pot and housing.