Mine had the Sony Am/FM Cassette radio when I bought it in 2015. I wanted to upgrade to a CD player with Aux so my Sirrus Sat radio could be connected too. Overall it was fairly simple.
Removed front of the Sony, loosened the washers and it dropped out from the front. The wire connections matched up with wire harness on the new Kenwood. Used the existing AmFM Antenna and it works great. After it was connected I realized I am missing a speaker over the dinette. My Landyacht was suppose to have 6 speakers, 2 in driver area, 2 in bedroom, and 2 mid cabin on both sides. Apparently they forgot to add the additional speaker in the mid cabin area.
Let me know if you run into any problems.