Although you are allowed a larger carry-on by the airlines...I usually use my Go Ahead bag as my carry on. If your tour is not full you can put your carry-on in the baggage hold on the coach...but if the tour is full, you will be responsible for carrying it with you and a full size carry-on may or may not fit in the over head of the coach. Currently airlines usually allow only 44 lbs for the bag you check and I'm infamous for not having my bags go where I'm paying the airlines to take them anyway. I pack a full change of clothes (except shoes), a book, my camera, my medications and some toiletries. I spent two weeks in Greece with only the clothes I carried over with me and 2 t-shirts I bought a few days before the tour was over. That was the trip that I discovered the value of nylon garments and undergarments that dry overnight..... I'm a 'real woman' (see that as super-size) and it's not always easy to find clothing.