Ilb, a friend of mine did a camping tour on his Allez with a pee-clip'ed rear rack and 40ltr Ortleib roll top panniers.
The Ortleibs are great as you can move the rack clips back and forth to match the rack or help on clearance.. He doesnt have Gandolf size feet however.
I can offer you:-
A touring bike. Dawes Super Galaxy 54cm with rear rack. Of which, if you get a large top trunk, will be fine. I have one but it will be just too small, possibly. And..
I also have Ortleib Front roller-city panniers 25ltr, that will fit on the back fine, or you can use too if need be. FAB panniers.
As you want to travel light, then I would look at either these smaller panniers on your bike (which I am sure will be fine for clearance) or a top trunk. If it was me, a top trunk.
I also have a spare rack if need be.
And dont bother with a rucksack...