I looked up your Greystone fireplace and it looks to be a 32 inch long model that has crystals which is very similar to the Furrion part # FR88FR which would be a great option for a replacement. We've found that the Furrion fireplaces are more reliable than the Greystone ones. This actually draws less amperage at 12 amps too. view full answer...
The heating element for your Greystone F4716W Fireplace in your 2018 Forest River Sierra HT 5th Wheel is not available, unfortunately.
With that being said, since this fireplace & its replacement parts have been discontinued, the best option is a complete fireplace replacement.
I know this may not be an ideal option, however the:
-Furrion RV Electric Fireplace with Crystals - 40" Wide # FF40SC15ABL is a great replacement.
This fireplace is a couple inches shorter overall but the actual... view full answer...
The Multi-Fit Motor Home Trailer Hitch, 47" - 71" wide # 82201 is a Class III hitch so you will be good to go with the system your referenced as long as it falls within its capacities. It has the 2 inch receiver opening you need and is rated for 300 lbs tongue weight and 3,500 lbs towing capacity. view full answer...