Racism? Why not re-conceive the retired black guy as a semi-retired fiction writer who moves to a nearly all-white touristy coast town like Aptos, or Eureka in CA or Florence in OR? A black unofficial detective newcomer and an all-white PD or Sheriff Dept. (plus or minus a token minority) would be perfect for the de rigueur conflict between the smart detective and dumb local LEOs. With that set-up CR just needs a good mix of villains and villainous victims (the latter getting long-delayed 9mm karma) in various forms such as a greedy developer wanting to pave Paradise, a loony-hypocrite Fundy preacher, or a local businessman dumping industrial waste for fun and profit (all whites, all racists, of course).
(Did I miss any derivative worn-out stereotyped plot lines?)
Since this is a DUmmy we're talking about, I'll flesh out one of your plots.
A White, Republican megachurch pastor is murdered in his church office. The culprit is a local mixed-race tranny who is actually the pastor's illegitimate son. The tranny went to the church for assistance, and the pastor tried to seduce him/her.
The protagonist (who is also a homosexual vegan) identifies the murderer, and in the process uncovers the town's dark secret: the victim had taken advantage of many poor minority women who came to the church for charity, and he had several mixed-race illegitimate children which he never acknowledged.
The protagonist then advocates for the murderer, shames the police chief into dropping charges, and leads a protest against the church. The book ends with the church's board agreeing to close down, sell their assets, and distribute the proceeds to the pastor's bastards as reparations.
