The GPS will take longer to get a fix if you have moved a long way since the last time you used it (or if you have not used it for a long time) because it stores information about which satellites to look for. It can take 1-2 minutes sometimes.
Also, you will not get a fix if you are inside any sort of large building. That includes hotels, office blocks, supermarkets, etc. You may get a fix inside a house, but there's not much chance with anything bigger.
I have used locus in offline mode (including no data of any sort) in China, and it worked fine. The maps in China are a whole other story :roll: , but Locus worked OK.