Plenty of campsites do have a back packer/bike packer policy and will fit you in. Only really getting into camping this year, usually in the car with loads of shizzle, but done my first bike packing this last week. Probably moving to getting a people carrier van, to carry bikes etc in the vehicle, but also be able to convert for a night here or there in the vehicle – don’t want a camper as won’t have space for bikes/paddle boards, but a shower/loo is nice (we take a porta potty camping for nights).
Must say, the pub we were at were perfectly happy for us to pitch up in the large beer garden – there was no-one there, was a Sunday evening, very few locals in, so they got say £50 of beer sales between the 3 of us (three rounds) (bar closed early unfortunately) that they wouldn’t have had.