I had a rather long post referencing a recent crs episode that my tablet destroyed--yes, I hit the wrong thing...again--agonizing over a sci-fan series from 1969 that I could not remember but eventually refound. I will not try to repeat that post.
I will, however, highly recommend Christopher Stasheff's "The Warlock in Spite of Himself" and it's subsequent books. I will also recommend Harry Harrilson's "Stainless Steel Rat" and its follow ons.
I don't know if these can be found free online. If they can't, I advise buying them. I think I will stop online reading for a bit and go back to my dead tree library.