STAR's and SID's

Hi All,

I tried plugging through the google newsgroups, with no luck.

I am currently a instrument *student*, doing my Multi-IFR stuff. I'm
Canadian, and some of this stuff isn't really covered in any of our
regulations or material from what I can see (unless im missing something),
and its a more "US Centric" question I have a question that I thought you
all might be able to answer.

Let's say I was instrument rated, and I was flying into a city like
Minneapolis, into St. Paul downtown, for example. (KSTP).
Let's say I was arriving from the east, from Wisconsin.

I looked at Minneapolis, and they have several arrivals, including ones like
the GEP.GEP4 STAR. My question is
a) if you were flying a piston single/light twin into KSTP, are you required
to file a STAR? It seems that by choosing one of the STAR's, you would
really have to go out of your way. I'm assuming of course, you could
intercept the STAR partway (not start it from the "initial fix"). Could you
just file an airway to STP then expect radar vectors for the approach? Or
should you expect the STAR as part of your clearance? Is it necessary to
file it?

b) Departing from STP, the only SID takes you to Green Bay or something
like that, which obviously wouldn't work if you were flying to , say, St.
Louis. Could you just file to intercept an airway and go from there?

What are the *real world* implications of flying into busy airspace IFR in a
piston single/light twin..this is all assuming that you do NOT have a way of
navigating direct (GPS), etc.

Thanks for any input.

Mark