Not that familiar with the Pro Randy but I'm thinking the regular MuffPot would fit on the pipe just like it did on the older Doo's. With the new hood on the 2013's the pipe isn't accessible very easily.
The muffpot does fit on the pipe of the Pro. I have one on my 2012. It will fit right were the pipe meets the can. I've heard of guys putting them on the bend of the can, as that is the easiest place to mount it. However, it doesn't really do the best job at cooking it. There are a few fixes where you can pound aluminium foil between the muff pot and the pipe to help increase surface area. I haven't done this myself but heard it works. Right now I just put lunch in in the morning and it's ready by lunch. However, the Thing can works awesome!! Went riding one day with a guy that has one, and he was cooking all sorts of stuff in 15 min or something like that. You could smell it when it was ready. That would be my suggestion, but if cost is an issue you can get a muffpot at most local dealers these days for under 50$
There is another option I saw, but forgot to mention. I have seen a guy mount his right up on the Y pipe. That would be plenty hot and do a really good job of cooking it, but you need to be very careful with how you mount it, so that you can get to it to get the pot in and out of the bracket, because there is VERY little space underneath the hood (and hot, bring oven mitts), but it is possible.