[plt-scheme] Interacting w/ MzScheme

I'm attempting to move from Scheme48 to MzScheme and had a few simple
questions. Primarily, can I do everything DrScheme does with MzScheme
instead? Using the DrScheme environment is a deal-breaker for me.

- How do I load DrScheme's module language into mzscheme? Also, how do
I turn on case-sensitivity?

- How do I enter a module from within the REPL to interact with it? In
s48 it's ",in module".

- Conversely, if I'm in a module, how do I go back to the top REPL? In
s48 it's ",user".

- How do I reload a module after editing it? Calling "require" again
doesn't appear to reload it.

- In the REPL, how can I access the previous output? In s48 it's ##.

- When I've created a unit, how do I use it within the REPL? It
doesn't like ^ in a name (signature^).

- Does mzscheme support interactive debugging? Inspecting data structures?

Finally, if these are answered in a doc I missed somewhere, please
point me to it.

Thanks.