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.
An explanation is given in the Tips, but I know it’s a lot of new information and some details are bound to be difficult to understand or slip through the memory. However, Duolingo has hidden the Tips, so I want to make sure you know about them and where to find them. If you have not been reading the Tips, I think you will find them very helpful.
If you are doing the course on iOS or Android, you cannot currently access the Tips through the app. To access the Tips, you will have to access the course using a web browser at https://www.duolingo.com/. You can still do it on your mobile device, but you will have to use the web browser instead of the app (or you can do it from a computer). When you click on a Skill, it will expand to reveal a Start button and a Tips button.
If you click on the Tips button it will show you the Tips and give you a detailed explanation of the grammar that is introduced in that Skill. If you have questions after reading the Tips for any Skills, we are happy to answer your questions, but many of your questions will probably already be answered in the Tips.