How could the people refuse to travel if the cloud went up from the Mishkan and they were still mourning Miriam’s death?

The rising of the cloud here is explicitly not mentioned in the context of a sign to travel, but rather that it was to enable the sunlight through in order to see Miriam's tzara'at, "And the cloud was removed from upon the Tabernacle, and behold Miriam was snow white, stricken with tzara'at, and Aharon looked upon Miriam, and behold, she was diseased" (Bamidbar 12, 10). Then God told Moshe that Miriam was to wait outside the camp for 7 days (as is done for tzara'at, v. 14), and that's why they didn't travel. It's not that God wanted them to travel and they didn't listen, but to the contrary, God told them to wait, and they also, with all their desire to finally enter the Land of Israel, they also willingly waited, to give honor to Miriam.