[dogscoff]

As far as I can tell, there was only 2 RD books ever written.

Nope, three. Red Dwarf, BTL and Last Human. Last human appeared several years after the first two, and (so I hear) closed the loop quite nicely and ended the series- BTL ended on a bit of a cliffhanger if I remember correctly.

But yes, very enjoyable. One of those books you can pick up and open at random and enjoy just a few pages, much like HHGTG in that respect.
Talkie Toaster is so much funnier in the books than the series, he's brilliant.