I can't remember where I found such a passage, but it is there somewhere. It even names some of the gods. If I remembered their names, then I could do a search. I need this information for a recent archaeology finding. It may be in the Psalms or prophets. I am not talking about the golden calf Aaron made.
Well, the BIG one is the golden calf they worshiped at mount Sinai. You can read about that in Exodus 32.
I wasn't able to find any other Moses-era or Joshua-era instances of ACTUAL idolatry, though. There's plenty of reference to worshiping other gods in Deuteronomy, but that's mostly Moses telling the Israelites that they SHOULDN'T worship idols, or that they someday WOULD worship idols, or that OTHER NATIONS were worshiping idols, etc.
There are also plenty of stories of the Israelites practicing idolatry from Judges on, (i.e. literally by the second chapter of judges it's happening). But I'm pretty sure they count as already having ARRIVED at the promised land by that point.
It will depend on your translation to get the name.
KJV Amos 5:26 But ye have borne the tabernacle of your Moloch and Chiun your images, the star of your god, which ye made to yourselves.
Septuagint Amos 5:26 26 Yea, ye took up the tabernacle of Moloch, and the star of your god Raephan, the images of them which ye made for yourselves.
KJV Acts 7:43 Yea, ye took up the tabernacle of Moloch, and the star of your god Remphan, figures which ye made to worship them: and I will carry you away beyond Babylon.
KJV 2 Kings 17:16 And they left all the commandments of the LORD their God, and made them molten images, even two calves, and made a grove, and worshipped all the host of heaven, and served Baal.
KJV Judges 2:3 And they forsook the LORD, and served Baal and Ashtaroth.
KJV Judges 10:6 nd the children of Israel did evil again in the sight of the LORD, and served Baalim, and Ashtaroth, and the gods of Syria, and the gods of Zidon, and the gods of Moab, and the gods of the children of Ammon, and the gods of the Philistines, and forsook the LORD, and served not him.
KJV 2 Kings 23:13 And the high places that were before Jerusalem, which were on the right hand of the mount of corruption, which Solomon the king of Israel had builded for Ashtoreth the abomination of the Zidonians, and for Chemosh the abomination of the Moabites, and for Milcom the abomination of the children of Ammon, did the king defile.