Please tell me what photographic equipment is suitable for the poor to take to Tibet.

You must bring it to Tibet, so you must bring Tuli 12-24.

If you go near the snow-capped mountains, you'd better have a telephoto. After all, you can't always shoot on the snow-capped mountains, you need a telephoto lens to take a long view. But you don't have telephoto at present. It seems a bit extravagant to buy a lens just for this trip.

It is suggested to take 18- 105 again. In addition to the big scenes and scenery, this shot is more convenient for shooting street scenes and temples.

If there is still room for equipment, you can take the 35 fixed focus with you and use it as a tripod head on the d90. It feels good to use it occasionally.

As for the tripod, if you want to go to road trip, you can put it in the car and take it with you when you use it. If you take transportation, forget it, it will affect your travel mood, unless you specialize in making movies.