@AZogas Cast iron grates are cool and give you nice sear marks.
They are also heavy and difficult to handle when they are searing hot especially compared to the light stock ones that you can remove easily with a pair of tongs.
The Go-Anywhere being a grill made for portability IMO doesn't need extra weight.
I like the idea (although I've yet to do it) of using a dremel to cut the stock grates on the sides so you you can remove one side to refuel.
The one's I've seen cut are cut down the middle, I'd probably cut it 1/3 and 2/3 to not have to lift as much of the grate off where there might be food.
Here's a demo-
https://www.youtube.com/watch?v=UsGMqHL70oc