But anything happening beyond the dialogue is implicit anyway, and I find it highly unlikely that Luke only constructs a new lightsabre at this point. A whole year of training without a lightsabre and then he races of into battle and managed to destroy Vader?
And you also have the problem that R2-D2 needs to have the lightsaber before Luke goes to the Palace. I don't remember any opportunity for R2 to collect it from Luke before that.
Also, a convenient out-of-the-way place for them to meet isn't necessary. Ben can appear to Luke anywhere he wants. I'm not saying I would dislike a scene taking place there, but it just seems a bit contrived and unnecessary.