I do the same since my stuff is higher miles now. Things like water pump, fuel pump etc. idk if there's any hemi specific things. This summer before our big trip I replaced the water pump because seems avg life is about 150k and was at 140k.
My suggestion would be read a bit on a Ram pickup forum. Scan thread titles for 3rd gen pickups and whatever you see as a common "xxx just broke on my truck" occurance, think about fixing it.
Also start a couple threads on there where everyone has a similar rig. Ask the same questions as here.
Then add up all the stuff you "think" you need to do and see if is worth it to you to do all that or dump the truck.
My other theory is do that he work yourself = fix it. Pay someone else to do repairs = sell it.
