Can you have two locatives in the same sentence like this? And how do I express "Meet me on Kronos AND in The Great Hall"?
You can indeed have two locatives in one sentence. Consider, for example, the Bird-of-Prey cutaway poster:
English sentence: 1st Construction Site: The Kling District, Klingon Home World Klingon sentence: tlhIngan juHqo'Daq tlhIng yoSDaq 'oH toQDuj chenmoHlu'meH Daq wa'DIch'e' Back-translation to English: The first location for producing a Bird-of-Prey was in the Klingon district on the Klingon homeworld.
There is also the idiomatic expression tIngvo' 'evDaq chanDaq, translated as "from area-southwestward to area-northwestward to area eastward", with the idiomatic meaning of "everywhere" or "all over the place". http://klingonska.org/canon/1999-11-21-news.txt
As for talking about two places: I'd probably split it into two sentences, but we do have at least one canonical instance of two locatives being joined by the use of je, same as any other nouns:
http://klingonska.org/canon/1995-09-holqed-04-3-a.txt English: The initiate must pass through a gauntlet of warriors who test him with painsticks. Klingon: poSDaq nIHDaq je QamtaHvIS SuvwI'pu'. chaH jojDaq yItnISlopwI'. [sic] luchovmeH 'oy'naQmey lo'. Back-translated: "While warriors are standing on the left and one the right. The celebrant must walk between them. In order to asses her/him, they use painstiks."
Although paq'batlh is a bit of a questionable source, being a work of poetry, it's worth noting that it also has an example of X-Daq Y-Daq je:
'ej Hoch vengHomDaq Hoch vengDaq je Suchbogh ghaH qeylIS luQoy woQ le'yo' je ‘aghbej ghaH
I don't have the English handy, but back-translated, it becomes something like:
"And in every village and in every city that [Kahless] visited, they heard him. He certainly showed authority and pride."
Further to this: Do the two locatives in this sentence modify the verb HIghom independently ("Meet me on Kronos, in the Great Hall!") or does Qo'noSDaq modify vaS'a' to make a noun phrase Qo'noSDaq vaS'a' "the Great Hall on Kronos"? The latter seems like the most natural interpretation of the English translation here, but whether a locative can modify a noun in Klingon seems to be at least controversial.