I am planning to do several overnight camping trips along the coast this summer but wondering if I might be able to get away with

I have a Carradice Camper and a Bagman Expidition QR. The Bagman states to hold up to 10kg (around 22 pounds if I am not mistaken). How many days can a person reasonably expect to travel with 1,400 cu. in. of space and a 22 pound weight limit? I was planning on buying food each day that I am out and only carrying dinner with me

I know the question is vague at best, but there is a lot of experienced riders on here and I was wondering if anyone has done something similar. I am guessing it would be a semi-supported (?) tour since I am planning on utilizing grocery stores and local eateries along the way and only carrying/cooking my dinner for each night and camping out...maybe staying in a hotel every other or third night (as budget allows).

I am no stranger to ultralight camping and still have most of my gear, but I have never tried mixing cycling and camping.