I've seen Backyard Starship recommended to me a lot on Amazon, mostly because of similar reading I do, I think. I might have to check it out. I recently read the Junkyard Starship series, where worn down old Vietnam vets get intelligent alien parasites that rejuvenate them, and off they go on interstellar adventures. They get 20 year old bodies, but keep their curmudgeonly old minds. Fun reading.