You should be able to do a lot with the standard "carry-on" and "personal item" that airlines allow. I've travelled to Asia and Europe with this carry-on combo and no checked luggage.
For personal item I have used a laptop bag, basically a briefcase. It accepts, besides a laptop, my 7D2, 100-400mm II, macro lens, backup SL1 body and 18-55mm lens, snack, water bottle, travel documents, and various other things. More recently I am using a camera bag as my personal item. It works better for the gear, but is less convenient for documents.
Less critical things like lens hoods, chargers, the laptop AC adapter, and a flash go in the carry-on, which is a roll-a-board. That's also where my clothing goes, and other necessities. I travel light. The clothing that I take is limited.
Works for me, but everyone is different. (I chuckle when I see guys with two big suitcases in addition to carry-on items.)