I think that Pilgrim's Progress is mainly readable as an anthropological/historical artifact.

I hated Gulliver's Travels with a passion, but I was thirteen or fourteen, so my opinion should be taken with a huge grain of salt.

I voted F on the Burroughs and the Smith because, while they're likely to contain some appalling things in terms of racism/sexism/etc., they were written with the intention of being entertaining.