As someone with a 40 year old clipper, the house is really the same. Other than possibly an electric/gas water heater, you can easily add anything you want that wasn't in the older MH - microwave, residential fridge, tv, etc.).
The biggest difference will be in the engine/chassis. And that will be dependent upon your wants, likes and needs (I love my ole' Dodge 360 engine and it works just perfect for me).
The outside will be dependent upon care over the years and original build. I've had fewer issues with leaks than many people with newer MHs and no delamination, etc.
