I tried to add a service reference to a WCF service that resides in the same solution from an ASP.NET MVC 4 project but failed. I got a error saying:
Do you really mean to return a node in an arbitrarily deep tree?
If so, then instead of returning a JToken, first convert it to a string to get the JSon text. On the client end, you can Jtoken.Parse(yourstring) back into a JToken.
If not, then consider passing back the Value and letting the serialization deal with T.