I feel your pain! :(
One way is a small watt inverter in the cig lighter to plug a CD player and a set of 2.1 speakers into, but there is no where to mount them and operate it all except the passenger seat. If DW along, the one in the passenger seat can be the operator.
Had Sirius radio briefly which somehow used the truck speakers. Didn't like their way of doing things. But there might be a clever way to still use your truck speakers instead of your own 2.1 set, don't know.
Note- a thumb drive is fine but you have no control over selection, skip and go back etc. If you just record from whatever playlist "they" have (like from Stingray) and don't like it all, just some of it. Plus it takes hours to do up a "play list" of only what you like, which could be better spent.
Another way is to get an older radio with a player from a junk yard and swap it in . :)