Rishonim on Locationality of Kiddush

Shmuel said: "There is no kiddush except in the same location as Shabbat dinner" and we normatively practice as he said.
And Rabbenu Nissim (1308-1376) wrote, "This is specifically that one did not intend at the outset to eat in another place."

1. Kiddush [is valid] only [if recited] in the place of the meal and in one house. [Changing one’s place] from one corner to another corner [in] the same [room of] a house [is not significant. If one recites Kiddush in one corner with the intent of eating there and then changes his mind [and decides] to eat in another corner of the same room in that house, even in a large hall, he need not recite Kiddush again.

RAMA: From the house to the sukkah is significant, like changing from one corner to another (Mordechai).

There are those who say that anyone who sees his place - even from a house to a yard - does not need to return and say kiddush again. And there are those who say that it is also reasonable if one says kiddush in one place with the intention to eat in another place. This is so if both places are in one house, for example from room to room or from a rooftop to the ground (and such is the essence).

2. If one makes kiddush in one house over a dish eaten there, and afterwards goes to eat in another place, must return and say kiddush in the place where he wants to eat.

3. If one makes kiddush but does not eat a meal (afterwards), even regarding kiddush he has not fulfilled his obligation.

RAMA: One must eat in the place one makes kiddush. However anyway, even if one eats in the place that kiddush was recited, one has not fulfilled (one's obligation). (Mahar"i) If it was his intention to not eat there immediately, and then he went and ate, he has fulfilled his obligation. (Beis Yosef, end of the Siman).

4. One may make kiddush for others even if he does not eat with them. [There is no difficulty that] Kiddush is not being recited in the place of the meal. And even though, regarding the blessing over the wine, others cannot fulfill their obligation through him if he does not receive benefit with them. How so? The blessing Borei pri hagafen of Kiddush – whether of the night or of the day – and the blessing HaMotzi when one recites Kiddush on bread do not resemble other birchos hanehenin, since they are obligations.

RAMA: Even regarding the kiddush of the day of Shabbat it is permitted to do this (Rabbeinu Yerucham; Beis Yosef in the name of the Rif; the Rosh; Tur).

And this is if they do not know. If one still does not make kiddush for oneself he must be careful not to taste it with them, because it is forbidden for him to taste until he makes kiddush in the place where he has his meal.

5. The Geonim wrote that this - that Kiddush may be recited only in the place of one’s meal, even if one ate something small or drank a cup of wine that required a blessing over it, has fulfilled his obligation regarding kiddush at the place of the meal, and finishes one's meal in another place; and specifically if one ate bread or drank wine. But if one ate fruits, no (he does not fulfill his obligation).

RAMA: Because of this, it was permissible for a mohel and a sandak to drink from the cup of the bris on Shabbat in the morning if they drank a shiur [Beis Yosef]. But it is the custom to give it to the baby [Hagahos Maimoni Chapter 29]

6. If one makes kiddush in his house and hears his neighbor (making kiddush), and a table is set out before him, he has fulfilled his obligation through him, because this is the place of his meal. This is provided the person reciting Kiddush has in mind to fulfill [his neighbor’s] obligation [with his recitation] and the neighbor has in mind to fulfill [his obligation] by listening.

7. There are those who say we do not say kiddush except by the light of the candle. And there are those who say that the kiddush does not depend on the candle. If he derives pleasure from it from the yard and eats there, even though he does not see the candle, the candles are for the enjoyment (of Shabbat) and not for troubles, and this is the opposite.