"Dear Dave" actually reminded me a lot of S1/S2 Rd Dwarf. Few extra characters (and none really seen save for letters and talking vending machines), few special effects, and some weird plot machinations that mean a lot for some reason despite coming from dead people or machines you can't possibly have a real relationship with.
Still really confused with this JMC thing. Aren't they all dead? Why are they listening to them now? The Space Corps apparently figured into the first episode too. Why is deep space, 3M+ years in the future so full of people from their time?
Through S7 or so, nothing they ran into (derelicts, etc.) came from any later than the 30th century or so. I always took this to mean that humanity died out or otherwise vanished around then, and the Dwarf crew were generally picking through the leftovers without figuring out what happened...